I think it would be easier to switch out the body in that case. You are going to have to be welding and fabbing in any way and moving the body would be less. You would have to build new mounts and figure out what the heck you are going to do with the guages and stuff but I dont think the rest would be that bad.
I've done the body swap thing ( Scout II body on a 79 bronco frame). I think the axle swap would be easier. Lots of wiring on the newer trucks with a body swap you have to deal with all that. Either one will not be easy but I think the axle swap would be the easiest :rotfl: :rotfl:
You don't really have to change the tranny just put the right output shaft and tailhousing on it the t-case you can use what the factory used or do your own custom setup you going to be doing alot of fab work anyway mine as well make it the way you want. Matt is probably right as far as dollars go you could make the body swap cheaper, It kind of depends on what you want are you just trying to make your 2wd a 4wd and leave it basically stock with just a mild lift on it. Or do you want a wheeling truck that is a custom creation also newer frames are stronger than the old frames. I would really look at the body mount locations on both see if they will interfere with anything on the old frame. Either way involves getting a donor truck mabey two to get everything you want . I think the hardest thing about the body swap is getting all the mounts to line up the first time and getting the body on the new (old) frame. You will probably have to run some fuel lines on the old frame too and then their is the wheelbase thing. Like I said before both are expensive and complicated when done right. :rotfl: :rotfl: