Frame a little thin.

[JOEGMC]

Hey guys its been a while since I was on here. I am trying to build my dream truck here and cant catch a break. I bought an 83 one ton Chevy to use my 77 body on. Well The frame has a few thin spots in the back, only on the bottom lip of the frame. I'm wondering what you guys think I should do? I live in PA, so there is no such thing as a rust free truck. Ive looked a few and this one seems to be the best. I'm just a little concerned about welding a frame. considering is a 1 ton truck that I'm going to use. The frame is pitted a little, but Ill know more once I get it tore down and get it sandblasted. I was going to box it all in, but after some research it sounds like most people don't suggest doing that. Any thoughts or suggestions would be awesome. Thanks guys!