I have participated in a couple classes from McCall Mtn. Flying and was very satisfied with the classes, the instructors, and the results. They are very close to a lot of good strips to practice on and some beautiful country.
If you live in Az. part of the year, they also offer a class out of Bluff Utah which intoduces you to many of the old mining strips in SE Utah., some outstanding scenery, and a good place to practice.
As said many times in here before, good idea to get some instruction in backcountry/mountain flying before doing many of these strips.
Good luck and fly safe Gary