Early Bronco frame under Bronco II

I purchased a 71 EB for $500. Ran rough and looks really rough. When you shut the door, enough rust falls out to choke a horse (ha ha). After install all new primary ignition, flushing the pond out of the radiator, rebuilding the carb and changing the oil, the thing ran better than my 07 F150. Drove to get inspected and they laughed cause of the football sized holes ALL over it (thank you, salty winter roads). The whole entire body inside and out is this way. I'm not rich so spending over $5000 on new tub and paint is out of the question. Plus, its for wheeling and sometimes driving to work. Finding good used tubs that are worth the trouble are extremely hard to find. So I was thinking about a B2 body or even a ranger, they are more plentiful and they look as if they will fit. If anybody knows of some information on this, I would greatly appreciate it. I really would.