[Rust-O-Matic]

If that's a pic of the actual truck and the frame looks ok, go for it. Almost all of these trucks end up with rust holes in the lower rear of the front fenders, rocker panels, floor edges, and cab corners to some extent. The rockers in that pic are way better than you would typically find here in MO. Patch panels are readily available from lots of vendors. Most parts, both used and new, are very common for these trucks so you shouldn't have any trouble fixing it up.

You've also come to the right place for info, these guys know their stuff. Good luck!