What is the best way to remove rust from my F250 frame?

I bought a 1994 f250 with about only 35,000 miles on it, however as the original owner used it to plow his driveway it has quite a bit of rust on the frame and starting to show tiny specks around some of the fender areas. Should I sc the rust with a hand brush or invest in a sand blaster- if I do does the body have to come off to do it? Also when I sand down the body do I use an orbital or angle type sander?