I also think that MIG will meet most of your needs. Taking a course is an excellent idea. I didn't and have done extensive body repairs on my 142E. Although most of it came out fine - particularly where the welds aren't right where you can see them - some of my mistakes (not filling in thoroughly between the tack-welds, not cooling down the metal sufficiently after each weld, and not enough hammering to relieve stress) are beginning to show on the outer sheet metal, and I'm going to have to do a bit of re-doing. However, I consider that part of the learning process. Doing it my way, it's best not to have an expensive paint job done until a few years after you've done the body work ;-)
Bob S.