Lesser of two evils

[dacanuck]

So I disassembled my 1987 and scrapped the cab and frame. I bought a 1986 shortbox with a 70's 350. The frame has a few holes near the left rear wheel and the cab needs corners and rockers which I have. But it has a sunroof that I don't want and it's pretty rusty at the back at the the bottom with one hole going into the cab. I don't REALLY want to replace both the frame AND cab since they'll be about $1000 Cdn each for used southern pieces. Which is easier to fix if I keep one and replace the other? I'm a capable welder but haven't done rockers/corners or patched a frame. I don't want anything fixed half-assed on this truck since I've finally decided on this truck as being the project.