Planning a Trip Over The Rockies

Around here (Western Canada) most of the neophytes who get into
trouble in the mountains crash because of weather considerations or by
entering an upsloping valley that the airplane can't outclimb and the
pilot waits too long before turning around.
Mountain weather is treacherous and can change very rapidly. Pay
attention to the weather briefers. Mountain clouds usually have rocks
in them.
Mountain valleys can be confusing, especially if there's no
highway to follow, and it's easy to turn into a wrong canyon and get
lost real quick. The route should be marked on the map, with compass
headings penciled in on each leg. For anemic airplanes like the 150,
wind direction over the hills can make the difference between climbing
and sinking, as can lift or sink generated by solar heating or shade
on the slopes.

Dan