You may already know this, but be aware that there are basically two kinds of "mountain flying" courses. One is of the mountain checkout/high-elevation type, which may be offered by most flight schools anywhere in or near the Rocky Mountains. These courses probably use whatever trainer they have available (172, Cherokee, whatever) to provide students with the knowledge and skills to safely operate in and around the local mountainous areas. These programs run a wide spectrum, from maybe a couple hours to an extensive multi-day affair (such as listed above.)
The other kind of program might be thought of as an actual "bush flying" experience, using off-pavement capable aircraft (Super Cub, Husky, etc.), and actually landing at some of the wilderness strips, most are in the states of Idaho and Montana (there are others, as well).
I mention this just so you know what type of course you may be looking at. Here's a couple of the "bush" variety, I do not have personal experience, but they have a good reputation:
Mountain Canyon Flying Seminars, Mountain Flying, Canyon Flying, Backcountry Flying, Adventure Flying, Advanced Flight Instruction, Aviaiton Safety Training, Idaho Wilderness, Utah Canyonlands, Flyouts, McCall Mountain Canyon Flying Seminars and
Welcome To Teton Aviation Center
If not already familiar, I'd suggest Sparky Imeson's Mountain Flying Bible, full of useful information, and nearly "required" reading for pilots around the mountain west, here's the link
Contact Us. Sadly, Mr. Imeson perished in a crash in 2009.
Hope this helps, good luck, and enjoy your visit!