1980 GMC K25 - Farm Truck from Hell!

[Devilman]

I'd take it to a body shop and have them check out the frame and straighten it if it's not to bad then do a small lift and 35s. Wouldn't hurt replacing the body mounts since it needs them anyways if they're the factory originals.
And leave the paint alone! Anybody can have a flat black rattle can job but no one has the paint job you have now, the truck earned it's bumps and bruises and deserves to keep em. At the most I'd replace the rusted areas with patch panels and prime them. Although that's just my opinion and I love the way your truck looks now.