"The Frog Idol has stood in the Black Mire for ages untold – an idol of an
ancient and forgotten god who now only manifests through this ancient
rock in a forgotten place. However, with the conquest of the dwarven
citadel of Kuln by the giants, adventurers have been seen again in the
city of Coruvon. And from Coruvon, the Black Mire is always in sight.
This adventure is designed as a site-based adventure setting for a party
of characters of levels 3-6 set in the Black Mire west of the city of Coruvon."

So I'm just catching up with the cancellation of GaryCon because of the pandemic & the fall out from the table top convention season. Sorry for all my friends who have had their plans changed & I hope that you stay healthy. Last night after I got home at five A.M. from gaming & what not I was poking around Dyson Logos site. I came across one of his older adventures done for the Fat Frog Challenge called “Challenge of the Frog Idol”, 'it is a 21-page digest-format PDF which is bit of a hex crawl with some railroad options built in (it comes equipped with a quest, but feel free to ignore it)'. We're gonna do a bit more then that today & that's because I was looking at Astonishing Swordsmen & Sorcerers of Hyperborea last night.
“Challenge of the Frog Idol” makes an excellent addition to 'The Black Moss Hag of Lug' starting adventure in the AS&SH rule book especially as the town of Swampgate makes a beautiful adventure addendum to city of Coruvon. The Black Mire featured in the “Challenge of the Frog Idol” fits the AS&SH narrative of the 'Green Death'. Because this is a Labyrinth Lord adventure it slots easily into the AS&SH system. The source of the Ironflow river could in fact be the source of swamps of Swampgate. Further dungeons could be placed within this area with little issue.

With a bit of campaign juggling on the dungeon master's part this whole adventure pattern could be used to tie the Iron Flow river into the villages of the NPC's that appear in Ben Ball's AS&SH adventure Beneath the Comet!
Beneath the comet is on sale right on Drivethrurpg.

I always loved the Peter Mullen cover on Beneath the Comet.
Now if the events of Beneath the Comet conclude & the adventurers want to get sucked into the area around 'Swamp Gate' Dyson's The Tomb of Durahn Oakenshield. This adventure has all of the hallmarks to keep this swamp filled Viking style adventure Hellromp going.

If the dungeon master wanted to keep up the theme of fetid swamp filled old school adventure then Merle M. Rasmussen's X6 Quagmire fills the bill nicely for the areas around Swampgate to be filled in with lots of adventure locations. This even includes a race of lost men ala another group of Hyperboreans deep in the peat filled hellscape of AS&SH.

So to recap for this adventure path it would be:
- 'The Black Moss Hag of Lug' from the AS&SH rule book
- Dyson's The Tomb of Durahn Oakenshield
- “Challenge of the Frog Idol”
- Ben Ball's AS&SH adventure Beneath the Comet!
- Merle M. Rasmussen's X6 Quagmire
This adventure path should with little issue take the PCs from level one through ten. Anything beyond that is up to the DM. But this fetid mini campaign should last a couple of months at least or longer!
So what do you do when the snow storms start coming in the middle of Winter and you can't get together with friends? Grab a solo module and get playing by yourself, keep your DMing skills sharp, and get some quick alone game time. So let's take a quick look at (BSOLO) Ghost of Lion Castle.

"'A great cat sits
upon the northern grasslands, my friend, waiting to pounce on
adventurers just like you.' As you part the tall grass with your sword,
the words of the tavernkeeper echo in you head.
'He was the
mightiest wizard we'd ever known, and that Lion Castle was his home.'
Your friends' voices mingle with the tavernkeeper's. 'He's but a ghost
now, haunting those halls, and waiting for an heir.'
The ground
rises slightly. A strong wind rushes through the field. Suddenly, the
grasses part, and Lion Castle rises majestically before you!
'Magical
riches await those who enter!' 'Beware of man-beasts!' Voices flood
your head again. Will you brave the haunted castle? Can you afford not
to? It's all up to you in this D&D Solo Adventure.
Ghost of
Lion Castle is for one player only, but that one player makes all of the
choices and enjoys all of the rewards. An entire castle and courtyard
await your exploration. The adventure also includes a complete solo
combat system."

Merle Rasmussen, of Top Secret fame created a surprisingly huge castle and this isn't actually that bad of an adventure considering how its put together. The wizard Sargon created an enormous stronghold of untold mystery and a surprisingly large castle in the shape of a giant lion. Your going to be facing down werebeasts, spiders, stirges, orcs, and the ghost of Sargon himself in search of an accursed treasure. Merle Rasmussen doesn't do a bad job with this module at all and there's surprisingly a good moving and quick adventure here. The maps are clear, the plot concise and the presentation is well done.

But could this module be used with a larger group of players and perhaps expanded upon? Yes as a matter of fact it could easily be worked into a larger party of adventurers and the hard work has already been done for you. Several map expansions are available right here 
I also think that Sargon and his machinations could easily be adapted to several retroclone systems including Astonishing Swordsmen and Sorcerers of Hyperborea. Hear me out before you might dismiss me out right. Given the placement of the ruins of Lion Castle its very possible that Sargon and his works might have been left overs from the Green Death. There's a feel to the solo adventure that this place has been brooding for a long time. Since The Ghost of Lion Castle isn't that well know the dungeon master has a perfect venue to modify this module for their own retroclone system. 
It wouldn't take a lot of modification to move Sargon's digs to the border areas of Hyperborea and given the nature of the monsters of Ghost of Lion a DM shouldn't have any problems using the AS&SH referee's book to reference about ninety percent of them for their own evil purposes. For other games such as Lamentations of the Flame Princess or Dark Albion's pseudo historical settings might mean making the castle a part of Fairy or a similar location of legend. But given the brutal nature of some of the elements of Ghost of Lion's Castle its not that hard of a stretch for a DM to modify it out for a more horrific feel. 
So is Ghost of Lion Castle by
Merle M. Rasmussen worth your time and efforts? I can honestly say that I think so, given how easy it is to modify, the story and background that the author has put into it. There's plenty of room to DYI this adventure for your own needs. There are copies going for fifteen dollars on Amazon and there seems to be plenty of copies of it. Its actually a nicely made and tightly created adventure for what it does which is solo play and choose your own adventure style.