I have had three Raider/Montero donors to my project. All from rust prone areas. They all had some rust, each in different areas!

Most common would the rear bumper, the edges of the wheel wells, the top of the rear wheel wells, and at the bottom of the rear door jams (where run off would make its way down.)

There isn't anyone here who would question the longevity of a well maintained SWB. There are some here that have seen well over 200k miles on original engine. Lack of maintenance, and the cooling system in particular, is the main culprit.

They say a Weber coversion will not pass smog in most places.

If you really want to have some fun, with minimal fabbing, consider the turbo swap...