USA is a big place with many different climates and rust issues. Where you are will have a pretty big impact on what you find. If you have the access to or money for shipping I would look in the arid southwest for good metal to start with.
Yes,can't argue with that.But,I can't see buying anything sight unseen,and I don't see myself traveling across the country to find a decent body.
I haven't started any hardcore searching yet,but it seems there are a lot of the AD trucks around here,that people have bought as projects.I found a lot of ads of folks selling AD trucks,in various stages and condition,without even trying.
I'm thinking it might be likely to find someone in the middle of a project who may be selling a pile of stuff due to loss of interest or something.Provided they haven't made a bigger mess of things along the way.
Picking up someone elses lost project on the cheap,is that in bad taste or bad karma?
I know,it isn't as sexy as falling in love in a farm field,but in these parts it may be more likely.