This blog got a mention on G+ thanks to +Brett Slocum & in this case the topic was one that I've had a bit of experience with. How do you weird up a classic adventure module in the vein of Lamentations of the Flame Princess? The actual question comes from Dismaster FraNe;
'Let's say you have some classic modules (Caverns of Thracia, Keep on the Borderlands etc.)
How do you weird them up in a LotFP style?
I
am running a classic fantasy dungeoncrawling (Tomb of the Serpent
Kings) but the idea is to expand the campaign outside and in other
places and dungeons along with the official LotFP ones.
My idea
was to have a multidimensional universe with different places like Weird
Early Modern Europe (the main LotFP setting) along with A Red And
Pleasant Land, Vornheim, maybe Carcosa, and "fantasyland" (classic
D&D fantasy, where the players now are).
I'd like to spice up fantasyland in a LotFP way though.'
Lamentations of the Flame Princess by James Raggi IV is a very solidly designed gaming system & offers some unique challenges when running PC's through its gaunt of weird adventure mixed with actual real world history. The setting is a dark & very twisted pulped out Europe during the ages leading up to the age of 'Pike & Shot'
So where does this put a classic module like 'Keep on The Borderlands?' It puts the keep right at center stage where the warfare of Keep of the Borderlands is a part of the wars of raging across a war wary Europe.
'Player characters begin by arriving at the eponymous keep, and can base themselves there before investigating the series of caverns in the nearby hills teeming with monsters' Since this module was written & designed by G.Gygax himself it seems that it might be out of place in in LoFP campaign. Nothing could be further from the truth if the module is set along the Black Forrest of Germany. The area has a rich history of mythology including fairy activity dating back thousands of years. Warfare stirs up the ancient powers of fairyland & then its all bets off as the humanoid's activity blends into the background of the violence of the events of 'Better Then Any Man.' Why I'm talking about the events of Better Then Any Man? Because everything in that adventure takes place in Karlstadt as the center of Better Than Any Man & the home of the adventurers.
Make sure before running that adventure as a prelude to B2 that you visit this blog for some solid advice & resources for 'Better Then Any Man.' 
The PC's are going to find out that something rather nasty is going on as they encounter an orc or groups of humanoids attacking a small village near the events of BTAM. This leads them into an encounter with the forces of the keep & the possible desperate situation of B2's fort's inhabitants. Remember the fort is a part of a backwater community. The PC's have just experienced the twisted reality of 'Better Then Any Man'. This is going to lead them into the Caves of Chaos which is not a part of our world but a part of fairyland. The humanoids are not what they appear but the damned souls of Rome's finest. In the 200 years between the reforms of Augustus and
the rise of Septimius Severus the Roman army fought to expand the Empire
and saw action in the dark forests of Germany. The Caves of Chaos claimed their souls & the generators of the place keep reincarnating them back as the slave troops of the supernatural forces of the caves. These poor bastards exist to slaughter, murder, and war. The PC's are going to need to end the madness & move on.
This adventure path leads directly into;"The end of the road. A lonely fort stands on the banks of a mighty
river. It is here the hardy bands of adventurers gather to plan their
conquests of The Hill, the hulking mass that looms over this tiny
settlement.
The Hill is filled with monsters, they
say, and an evil witch makes her home there. Still, no visitor to The
Hill has ever returned to prove the rumors true or false. The thrill of
discovery is too great to pass up, and only the river stands in the way.
The adventurers' boat is waiting!'B5 Horror on the Hill by Douglas Nile from 1983 at first doesn't seem to fit into the Lamentations of the Flame Princess aesthetic. This is where there are two things to remember like B2 Horror on the Hill has a PC base of operations in this case Guido's fort & the events of this module are going to be taking place within an adventure location with connections to fairy.
The infinite tower location from Better Then Any Man might well be connected with events of Horror on the Hill & its easy enough to replace Guido's Fort with the Keep from B2.
The goblins & hobgoblins are going to have to be much more dangerous & metal for Lamentations implying that perhaps the dungeon location is one that switches back & forth between the real world & reality. This is perhaps because the alien reality of fairy has in the past taken various places back to the unrealities of fairyland. Time runs different, babies are kidnapped & possibly eaten, the connections to the damned & dead are very real. All of the weird bits of the fairy legends are true & very dangerous. This is also going to mean that the realities of adventuring are going to have unforeseen consequences for the PC's. Treasures & relics taken might be cursed or turn to leaves. Lives of PC's wasted at the drop of a hat for the false promise of riches & perhaps the various Elves & Dwarves of LoFP long for fairy but are denied memories of it.
A vital clue or two might lead PC's into a time warp & gateway from B5 into England of 1620 & the events of No Salvation For Witches by Rafael Chandler . Why? Because the stop gap gives the PC's a chance to experience the horrors of the meddling of man kind with the 'forces of beyond'. It also gives the dungeon master a chance to connect the random demons of No Salvation for Witches with events of B5 Night's Dark Terror. Note that this adventure path is going to chew through a lot of PC's. This is alright because this is LoFP. 
Because B10 Night's Dark Terror is a wilderness based adventure with lots of B/X campaign setting weirdness in it. According to the Drivethrurpg entry; ""Night's Dark Terror" marks the start of the second wave of Known
World creativity, following the period from 1981-1986 when it was
primarily the vision of Zeb Cook. It was also the third great touchstone
for the setting, following its introduction in the D&D Expert Set
and its unification in X10: "Red Arrow, Black Shield".
The adventure details many of the wildlands of the Grand Duchy of
Karamekios and also introduces new peoples such as the ancient Hutaakans
and the Iron Ring slavers. It extensively describes several major
locations, such as the city of Threshold. A magic tapestry of the lands
that appears within the adventure really helps to define B10 as the
gazetteer for this part of the Known World. " This is fine because it marks B10 as being a perfect vehicle for an early Russian or Romanian historical adventure. This means it can be married up quite nicely with a secondary campaign setting that the players are not going to expect in the form of Zak Smith's A Red & Pleasant Land or Zak S and James Edward Raggi IV Death Frost Doom In fact because of the wilderness crawl aspect of B10 both adventures can seamlessly fit into the whole cloth of the campaign & adventure path with none the wiser. Don't over explain the mysteries & weirdness the players will do all of the heavy lifting for you. 
Hopefully by now in the campaign some of the adventurers are going to retire to Karlstadt or have taken over the keep & their ready to retire. Another generation of adventurers can take up the mantle at the point. So what might happen? Well new adventurer PC's means new opportunities & here I'd use England Upturn’d by Barry Blatt as an adventure set during the English Civil War with an entirely new cast. Things are going to be very desperate & the various factions of this adventure means opportunity to run perhaps the Sinister Secret of Saltmarsh trilogy right into the background with a far more Lovecraftian flare.
This secondary adventure path gives the dungeon master the opportunity to introduce Carcosa & Isle of the Unknown to the unsuspecting players. By dropping clues from England Up Turn'd some faction might want to mount expeditions to the fabled 'treasure islands'. By dropping in X1 Isle of Dread but placing the adventure on Carcosa gives the DM the opportunity to watch the sheer panic. 
There are several things to keep in mind when threading in & out of this sort of a weird fantasy campaign. All of the LoFP products are not simply adventures but whole cloth source book which often have a real world history component. This dark history version of Europe is the default setting for LoFP princess and lends a great deal of gravitas to the various Lamentations adventures. Dungeon masters should not ever feel constrained to not modify or edit either the classic era TSR adventures nor the various Lamentations of the Flame Princess adventures as the whims of the players & the campaign dictate.
In fact part of my own inspiration for tonight's commentary & adventure path was inspired not by the usual Robert Howard's Solomon Kane but Dark Agnes de Chastillon who might be thought of as the spiritual ancestor to the Flame Princess;
"Dark Agnes de Chastillon (also known as
Agnes de Chastillon,
Dark Agnes,
Agnes de la Fere and
The Sword Woman) is a fictional character created by
Robert E. Howard and the protagonist of three stories set in 16th Century
France, which were not printed until a long time after the author's death.
The character of Agnes was beaten by her father and almost forced
into an arranged marriage. She avoids this by killing the bridegroom and
running away. She meets Etienne Villiers, who at first attempts to sell
her to a brothel, and Guiscard de Clisson, a mercenary captain who
trains her as a swordswoman. When de Clisson is killed, Agnes heads for
Italy with Villiers.
Like the later character
Red Sonja,
who was based on another Howard character, Red Sonya of Rogatino, Agnes
has red hair and a short temper. But while Red Sonja's skill in the
handling of swords is a divine gift, Agnes's skill is a mixture of
innate talent and training.
The character may be partially based on
Novalyne Price.
[1] Fictional prototypes include
Jirel of Joiry, created by
C. L. Moore. Moore was enthusiastic about the first of Howard's stories:
[2]
My blessings! I can’t tell you how much I enjoyed “Sword-Woman”. It
seemed such a pity to leave her just at the threshold of higher
adventures. Your favorite trick of slamming the door on a burst of
bugles! And leaving one to wonder what happened next and wanting so
badly to know. Aren’t there any more stories about Agnes?"
