Well, about the 235, back when, they hauled loads all over the country. I don't see a big issue on that but you will spend a lot of time in the slow lane.
More important is Truck in good shape, engine and trans in good shape and a rear end with the right gear ratio to do what you want to do with the tires you want to run.
As far as rear ends go I think you are on the right track and just need to get the tape measure out and start measuring. I talked to my buddy who used to run a "corporate" 14 bolt under a little flatbed 53 3/4 with 3.73 gears and he said it did well. He thought it was close to the right width for a fendered truck.
