shouldn't be to hard to find a door for the dodge.
and if you did the truck on a 4x4 dakota chassis the fenders would probably work out great.
years ago my son RJ put a 46 cab on a ramcharger chassis and he had 36" tires and he opened the wheelwells up about 3" for better clearence, the extra width of the fenders worked out for him...
the green cab look like a 35-38? chevy/gmc.
here is a 37 chevy and the cab you are looking at notice the body lines.