Was that 53 with a flatbed a big truck (like 1 1/2ton) or a pickup size?

Pretty much anything bigger then a 3/4 ton will have fender extensions that bolt to the front fenders. These are for clearance of the big wheels and create much more work when lowering the truck. (see the pictures of the cab on the trailer)

If your truck has the standard pickup front fenders, life will be easier, I think.....

Dakota frames are great starting places. They have a good frame with demensions that are easy top work with. I've not swapped a truck cab on a Dakota frame, but have swapped a 50 big truck cab onto an 80 Dodge frame. I'd think the Dakota frame would be a better fit. The short box 1/2 ton frame I put under my 50 was not an easy swap.

At any rate, the biggest issues with any frame swap is width od the wheel track, followed by the relationship between the tire in the wheelwell and the engine/firewall clearance. I don't believe the wheel track will be an issue, but when you start lowering things, lots of strange things start happening. On the full size frame, with the wheels centered in the wheelwells, the engine sat back far enough it interferred with the firewall. To clear the engine, a cut in the firewall the width of the engine and 6" deep would have had to be made. That would have put the "new" firewall almost against the front edge of the dash. A Dakota may work out much better because the engine is almost cewntered over the front wheels where a full size truck the front of the engine is centered over the wheels. Might be enough to eliminate the firewall cut, or at least reduce it. A 3" intrusion into the firewall would be acceptable, 6" is really pushing it.
You will also need to fab cab mounts, and a radiator support because the 48-56 truck front sheet metal hangs off the rad support. Also expect to fab some sort of box (or modify the frame length) because the rear wheels will probably be in the wrong position.

If your truck has the fender extensions, plan on building new front fenders, or doing major modifications to the existing fenders. The extension adds about 4" per side to the cab width and the arch is very large and very long. At very least you will need to reduce the size of the arch, ahorten it by about 10" and reduce the width. Then you will need to make a filler pannel to take up the space of the reduced size arch. The good part is you can modify where the center of the wheel opening ends up being. That helps with firewall clearance.

If your truck has corner windows, chopping the top is also a challenge, but doable if you like that sort of thing. Gene