One other point to consider is the frame size. Some of the 1/2 ton trucks in the 1980's had thinner gauge frame rails. The 4x4 trucks and some of the heavier duty 2 wheel drive 1/2 tons had frames that were the same size as the light duty 3/4 ton trucks. There was also a difference in the width of the frames. I think the 1/2 ton trucks typically had 6 inch frames. These could be either the thinner or thicker gauge metal. The heavier duty 3/4 and 1 tons had 7 or 8 inch frames. The longer wheelbase frames were often made of the larger size also.

Personal opinion: If you are going to do a frame swap, use one of the heavier duty frames. It will come with the stronger suspension parts, etc. It seems like the heavier duty trucks may have also used the Dana 70 rear axle. I believe it was Gene who suggested considering a newer frame. That is probably a good idea. Make sure it is safe to cut or weld the newer frame. (Assuming it need to be modified to fit under the older truck.) I've heard some of these newer frames (Hydro-formed type??) can not be welded like the old frames. I don't know what year that started though. (I'm not even sure if Dodge made such frames of it it was some other manufacturer.)

If you will be towing close to a 10,000 lb. trailer, you need a real stout truck. I made the mistake once of pulling a load that size with a light duty 3/4 ton truck. It was originally a 360 powered truck, but a 318 had been swapped into it at some point. The truck had 4.10 gears with a 4 speed. I had to pull that heavy trailer up a long steep grade. Near the top of the hill, it was real questionable whether it would have enough power to make it up the hill. You do NOT want to find yourself in that situation!!!! If you are going to tow that much weight, have a truck that is capable of handling the load.

By the way, I LOVE the idea of using an older truck to tow a vintage camper. I've wanted to do that as well. Unfortunately, there are other priorities in my life currently.