So I looked at this 2008 FJ today. It has 133,000 miles and the body and interior are in excellent condition. The engine and tranny seem to be great as well. It drives great. However it was a northern vehicle and has a lot of rust underneath even a few spots on the frame where it has rusted through. The guy is asking $14,000 and I told him given the issues with the rust i’d be a buyer at about half that. What do you think I would be into to maybe get it sandblasted, the rust cut out and new metal welded in as well as replacing bushings and other stuff that are probably shot due to the salt as well. Anyone have any experience with stuff like this? I have a lot of experience building forerunners I’m on my third one. This would be for my son though. Just looking for some thoughts and feedback and if anybody has any experience mitigating rust issues like this.

Rust never sleeps, so it will keep getting worse.
Sandblasting, treatment, welding on plates is what has to be done.

I wouldn't even mess with it. If its as bad as it sounds probably will just un-cover more and more once you sandblast it.

Yeah, I would pass on this one.