Here is my five cents worth,
I learned a lot about mountain winds and turbulence thru my 1200 hours of flying gliders cross country in the Alps - yes glider pilots do not fly when weather is bad, but does not matter much. I can tell you that you need to know a lot of fine details about air currents if you want to fly hundreds of kilometers thru the mountains without engine. May I suggest you get acquainted with glider pilots with mountain crosscountry experience-if you have a chance, try it (would reccomend high performance glassfiber glider, not some mediocre tin plane) It is great fun too!
Also, books on crosscountry soaring will tell a lot on this topic.
When flying into the mountains on a rescue mission as hoistop on a good thermal day, I sometimes feel terrible urgency to "redirect" my pilot when he is using raw power to climb instead of using a little bit of soaring techniques.
Regards,
hoistop