I have recently relocated my twainsgeography site to Amazon's cloud 
server and am combing through my site for bothersome details.  For those 
interested in such minutia, Fears' Day by Day contains this passage:

"The pair set off with an old guide and climbed on foot up through the 
pass, coming down a precipitous trail to the village of*Leuk***(a short 
distance from*Leukerbad*)[Rodney 106]."

Fears apparently got this from Robert Rodney's "Mark Twain Overseas".

The order of villages is actually reversed.  Leukerbad is the village 
with the baths and is found at the base of Gemmi Pass.  Leuk is the town 
to the south of Leukerbad.

Just thought I'd mention it... 
http://twainsgeography.com/content/kandersteg-leukerbad