Being a fan of geography, when mapping mountains (or other areas exhibiting changes in elevation) I typically map it topographically then super-impose structures over it. You local map store should have some ready made topographical maps that you can adapt to suit your purposes.
*** A Forgotten Realms Addict since 1990 *** Treasures of the Past, a Second Edition Play-by-Post game for and by Candlekeep Sages--http://www.rpol.net/game.cgi?gi=52011
I don't know of any specific mountain maps, but my Yahoo group has links to several locations on the net for maps.
Session Reports posted at RPG Geek. Stem the Tide Takes place in Mistledale. Dark Curtains - Takes place in the Savage North, starting in Nesmé. I wrapped my campaign into the Hoard of the Dragon Queen, but it takes place in 1372 DR.