x2 on the harshness. If the repairs make it safe, then repair it. "paid for" beats the living snot out of "paying for". I would not want payments on a truck put together by a bunch of union guys who thought they were on their way out the door. It would be like a truck put together on a Friday before a long shutdown times 1000. No freakin' way.
If it is solid except for the bushings, do the bushings. I have had to do all 4 leaf spring mounts and will have to do the bushings at some point because of the salt.
Southerners seem to freak out at any rust on a vehicle. Up here a shop will say "That looks really good for 15 years outside. You really take care of it. It looks like it was garaged." I had it in a couple of shops down South for some maintenance I could not do on the road. They said "I need to tell you this thing is really rusty underneath. It either sat for a really long time or was in the salt, it looks bad." I guess they missed the New Hampshire plates. All the metal is solid but it will eventually rot. That is why they have so many trucks from the 1970's on the road. Up here they are all dissolved.
My u bolts are still fine after 15 years outside it is the mild steel they use for other parts like the leaf spring mounts that bugs me.
I would not use rust proofing over rust. I wouldn't use it at all. I have not seen it work well enough. Paint is fine. Just wash it a lot.
95 Ranger Styleside SWB 4X4, 3.0, Auto, 4.10, 145,000 Miles
Century Cap, BF Goodrich All Terrain 30x9.50's, Reese Hitch, K&N Air Filter, Taylor Wires, Splitfire Plugs (I have had good luck with them), Bed Mat, Upgraded to factory alloy rims from "argent wheels", Cat, Dynomax Cat Back, Additional Battery Charging System, Transmission Oil Cooler, Grizzly Grill/ Brush Guard, Hella 500 Amber Fogs, Chrome Diff Cover, Nerf Bars, new bumper.
Upgraded to NH registration from Mass (Best upgrade!)
OEM Tube Rear Bumper, Tow Hooks, 31x10.50's, Larger or Additional Fuel Tank, Locker