Until you address the rust, I wouldn't put another dollar into it for offroad use. First, I'd buy a cheap camera to fully inspect the inside of the frame. It's also a good idea to:
- remove the inner rear fender liners and inspect there, especially the inner rear quarter panel areas (basically on the inside where the rear tail lights go.
- remove the gas tank and inspect the floor and cross-member areas, including the inner channels where the rear bumper goes
- inspect the inner rocker areas
- lift the carpet and inspect all the floors (Inside and underneath)
- inspect all the body mounts (My bet is that some of the bolts would break off if removed)
As you already know, rust typically works from the inside out, so inspect every place you can, remove all rust scale (and grease and oil), then treat it with some sort of rust converter, self-etching primer, then liberal coats of paint. It's also your choice as to whether you treat the internal frame with Fluid Film, or something like an Eastwood coating. Many here seem to like the Fluid Film route.
Once you've done all this, you'll know whether you want to dump anymore money into it, or start over with something new. If you do start over, you'll know exactly what to look for!
- remove the inner rear fender liners and inspect there, especially the inner rear quarter panel areas (basically on the inside where the rear tail lights go.
- remove the gas tank and inspect the floor and cross-member areas, including the inner channels where the rear bumper goes
- inspect the inner rocker areas
- lift the carpet and inspect all the floors (Inside and underneath)
- inspect all the body mounts (My bet is that some of the bolts would break off if removed)
As you already know, rust typically works from the inside out, so inspect every place you can, remove all rust scale (and grease and oil), then treat it with some sort of rust converter, self-etching primer, then liberal coats of paint. It's also your choice as to whether you treat the internal frame with Fluid Film, or something like an Eastwood coating. Many here seem to like the Fluid Film route.
Once you've done all this, you'll know whether you want to dump anymore money into it, or start over with something new. If you do start over, you'll know exactly what to look for!