anything can be put on a rotisserie, trying to separate the body from the frame would be crazy, it's a one-piece assembly with the frame
How bad is the rust? does it need major surgery? or do you just want is clean and painted?
the rotisserie would be great if you want to blast everything and paint the whole underside.
I spent 6 months on my back scrubbing, scraping, sanding, and painting the underside of mine in sections, but it's spotless and zero rust. Mine was painted already on top when I got it, so I didn't have the blasting option.