M1: Blizzard Pass

Module M1 "Blizzard Pass" by David Cook is a Basic D&D solo adventure for thieves level 1-3 (a nameless, pregenerated 1st level thief is included).  A separate section alternately covers play for a low level party of adventurers.

Title page to module M1 "Blizzard Pass" (1983) by David Cook.  Illustration by Harry Quinn.

The module was edited by Troy Denning (later co-creator of the Dark Sun setting), and features some great interior illustrations by Harry Quinn and Jim Holloway.

An invisible ink pen was used to reveal the hidden entries (also viewable using a blacklight).  Individual entries are available at The Blizzard Pass Project and here.

I've only played through "Blizzard Pass" once, but found it very enjoyable, (making it all the way to "the Master's" quarters before getting killed).

Blizzard Pass:

Possible location for Blizzard Pass "the treacherous path that winds over the Cruth Mountains between the Five Shires and Darokin".

The adventure begins within the Five Shires, with the main character pursued by a mob of angry peasants:

"There's the cur!" a man snarls.  The peasants have found you again.  The crowd presses closer, their dark faces twisted with anger.

"Murderer!" cries an old lady.

"I was framed!" you gasp.  The peasants will not listen, even though what you say is true.

"Kill the swine," says a flat, even voice.  The words are backed by the authority of the sheriff.

from M1 "Blizzard Pass" by David Cook

These sound more like humans than halflings, although mention of a sheriff suggests that Cook might have originally envisioned halflings (which I think suits his sense of humor).

Location:

Regarding a location on Mystara:

Q. Where would Blizzard Pass (of module M1 of the same name - the old D&D game invisible-ink module) be on the map?  It's supposed to run between the Five Shires and Darokin.  Does it lead to Mar or Hinmeet?

A. The location was never established, but it would be logical to place the pass between the villages of Ringrise and Hinmeet (looking at the color mapsheet of the region).  The pass between Sateeka and Mar is too well travelled and at too low an altitude for this type of adventure.

Dragon #184 (August, 1992)

Dungeon design is discussed over at Zenopus Archives, here.  (See also Mapping of Blizzard Pass by Robin on the Vaults of Pandius for additional details.)

Stodos:

There are details regarding an evil B/X god, with great potential:

As you advance into the room, you see a magnificent white statue of a toad-like creature resting in the center of the room.  The body of the stone beast lies close to the ground, as if ready to spring.  Your lantern light glitters off its enormous multi-faceted eyes, making the statue seem almost alive.

Illustration by Harry Quinn

Roderick circles the statue slowly, studying it from all sides.  Finally, he says, "If I remember my studies properly, this is a statue of the vile god Stodos, called Master of the Icy Wastes by his worshippers.  This evil god lives in a frozen world where no other life survives, and is an abomination to all things natural.  His worshippers desire to spread his icy realm throughout the land.  Some even believe he bestows power over the elements upon his most devoted followers."

"The unnatural storm that brought us here!" gasps Salamdros.  "Could his vermin have caused such a thing?"

Roderick thinks for a moment.  "Yes," he finally answers, "and if so, the lands below face great danger.

from M1 "Blizzard Pass" by David Cook

Group Adventure:

The group adventure is designed for a party of four to five characters (levels 2-3), comprised of all major classes (the Background states "You recently took passage aboard a caravan travelling to Darokin across Blizzard Pass").

New Monsters:

Rock or Cave Toad, Snow Ape