Rust on '78 Newell

[Brent Coursey]

We are looking at buying an older Newell in the '78 - '82 year range. We looked at one that had alot of the metal panels underneath the coach rusted out and this caused some rot on the plywood panels above the metal. I also noticed a crack on the external skin about 4-5 inches long above the entry door. My question is, when you see rust like this, how hard is it to fix? Could the crack above the entry door be signs of some internal structural problem. The coach has 475K miles on it. As a general question, what should we be looking for in a coach of this age.

Thanks In Advance