This book was a particularly enjoyable one to work on, in no small part because of my co-authors—my very skilled sometimes- co-conspirator Mike Ferguson and the fearsomely talented Richard Pett. The compilation offers a nice blend of pulpy Cthulhu adventures set in foreign locations: the Amazon (Ferguson), Sumatra (Pett), and Tibet (my bit).
Tibet was my first choice for location, and an interesting one it was. Even today, travelers to Tibet find a region steeped in unusual history, sometime-curious beliefs (at least to Westerners), and mystery. I suggest that anyone seeking inspiration for Tibetan adventure seek out the writings of Alexandra David-Peel in particular, as there's much to feed the imagination there.
My goal in this adventure was to cut the characters off from civilization, and to create a setting devoid of the usual comforts. In the middle of Tibet in the 1920s there were no phones, no modern transportation, no police, and no relatives or ready help of any kind (except that found in the location populace). I thought this fit both the investigative nature of the game (quiet investigation over seeking aid from the authorities) as well as the pulpy tone of this adventure line (when do Indiana Jones type adventurers going running to the cops?). And if some nameless horror slaughtered you in the wilds of Tibet, it might be a long time before anyone realized what happened to you...
The movie Hostel wasn't the greatest thing put on film by a long shot, but I do think the movie conveyed that fear of being in a foreign place away from the familiar. Touristas and a few other films that followed likewise tapped into this. When in other country you place by their rules, and sometimes that can be downright frightening.And we can of course find fear of unknown lands within in the bounds of our own country, as seen in Deliverance or The Blair Witch Project.
Lovecraft of course touched on this fear of unknown lands himself—unusual towns (Shadow over Innsmouth coming to mind first there), remote locations (Colour Out of Space or Whisperer in Darkness), foreign countries, Arctic desolation (At the Mountains of Madness), and even deep underwater environments (The Temple). Decades later, authors continue to combine unusual/remote locations with the supernatural/mysterious, such as Michael Crichton's Sphere or Preston & Child's Thunderhead. It's a most effective combination.
So if you run The Long Reach of Evil for your group, do treat them to a bit of sinister culture shock, Call of Cthulhu-style, before you allow the revolvers to be pulled from their holsters.
