Reviewing Astonishing Swordsmen & Sorcerers of Hyperborea in Preparation for a Campaign

It's been a while since I've done an old school D&D style campaign. I'm in the process of prepping it, aiming to kick it off some time later this month (or early in the next).

We'll be using Astonishing Swordsmen & Sorcerers of Hyperborea. AS&SH is awfully close to 1st edition AD&D, at least mechanically. However, there's a number of key differences I'm keeping in mind:

• The game is closely linked to the Hyperborean setting. This is strongly inspired by Clark Ashton Smith's Hyperborean stories (no real surprise there), with some good does of Robert E. Howard, HP Lovecraft, and Fritz Leiber (among others). It wouldn't be impossible to pull from the setting, but the setting is a great old school setting, one which on its own is very flexible and easily fine-tuneable by the GM.
• All the characters are human, though there are different human ethnicities or races.
• Like the Holmes edition of D&D, there are five, not three or nine alignments. They are Lawful Good, Chaotic Good, Neutral, Lawful Evil, and Chaotic Evil. 
• There is no multiclassing. However, the main four classes all have subclasses which simulate the most common multiclass options - it's easy to make a fighter/magic-user type for example, as well as magic-user/thief characters (good for your Grey Mouser for example).
• While there is no skill system, the physical abilities have rules for various physical tasks. 
• Classes like magicians and thieves are more useful at first level.
• While combat is not as crunchy at it would be in 3.x rules, combat rules are less fuzzy than earlier editions of AD&D and D&D (this is true of a lot of rules - there is a lot of tightening up of rules).
• Outside of potions and scrolls, no one knows how to make magic items any more. Aside from perhaps the creepy dwarfs living underground. 
• The world is fairly small, not much more land mass than that of the "Known World" of the D&D Expert Set. You can sail to the borders of the flat realm, taking you to waterfalls dropping into infinity. This is not a good idea.
• Winter is coming. The world's true year is actually 13 "years" long. The land exists as if it is north of the Arctic Circle. As a result one out of every thirteen years is dark all the time. And one year out of every thirteen is daylight all the time. I initially wasn't too crazy about this, finding the idea of a year-long winter makes suspending my disbelief difficult, but I'm starting to get some interesting ideas from this.
• The world is only now beginning to recover from a plague that wiped out perhaps 90% of humanity. This is rather handy for ruins, partially empty cities, etc.
• While it is a world of magic, there are also traces of long-lost super-science.

So how do I plan on using this? Perhaps the most important thing is it is "close enough" to traditional D&D that most old adventures will work just fine with it, albeit with some modifications. For example, I could see using classics like In Search of the Unknown and Against the Slave Lords adventures in Hyperborea. This is especially handy with grad school starting up again soon for me. Five more classes to go.

However, I do have some ideas germinating to take advantage of the setting. There's got to be some people on Hyperborea who want to return it to Earth. That could make for some interesting adventures - I wonder what year it is on Earth? Having just watched Peter Capaldi's last two regular Doctor Who episodes (just a Christmas special to come), I've got Cybermen on my mind. I wonder what some mad scientist or sorcerer might cook up to make his people better able to survive Hyperborea's brutal winters? Cybermen and zombies! 

I also enjoy the literary aspects that AS&SH emulates. While I'm not too up on Robert E. Howard, I greatly enjoy the tales of Leiber, Lovecraft, and Smith and will do my best to integrate their ideas into the game.