It looks like you'll have to pull the glass. Then I'd start by cutting out only what you need from the DONOR cab, then lay your patch panel over the rusty area and use a sharpie to mark the surrounding steel. Cut on the INSIDE of your sharpie line or your gap will be huge, and that's no bueno. Now since I cannot actually see the full extent of the rust on your cab, it may be more feasible to fix the other cab instead. That's up to you though.
1949 Dodge Coronet 1955 2nd Chevy 4400 1.5 ton 1955 2nd Chevy 3100 1/2 ton 1955 2nd Chevy 3100 1/2 ton 1957 Chevy 5400 LCF 2 ton 1966 Dodge D100 Sweptline 1968 Chevy P20 stepvan 1969 GMC LWB pickup 1972 GMC Sprint 1974 CP30 shorty bus There are three things that I've learned never discuss with people: religion, politics, and the Great Pumpkin.----Linus Van Pelt Trying to understand the behavior of some people is like trying to smell the color 9  | 
