I bought my welder at the Home Depot. It's the Lincoln 175HD. It's awesome. It's 220 volts though. You can also get the 3200HD which is a 115V model. Both are wire feed. Mine is super simple to use. I've never taken any kind of classes or anything. After 10 minutes of practice, I was welding up stuff for my bus! I welded up a mount for a new drivers seat in my bus! Works great! With the 3200HD, you could easily weld metal that is 1/4" thick. I can't imagine that you would ever need to weld anything thicker for your bus. Check out
http://www.weldingweb.com. It's a forum like this one. For the hobbyist like you and me, I think you'll find that they recommend the Lincoln welders. I am extremely pleased with mine. It's fun to use! The 175HD runs about $600. The 3200HD runs about $460. I've given thought to picking up the 3200HD because it's 115V. I could use it in a lot more places. As far as generators, I don't know what it would take to run one. I think a 2000W generator would do it, but you still might want to find out for sure. I have a couple of Honda EU2000i generators. They are absolutely fantastic and blow away any other generator on the market. They have LOTS of skoolie uses!