It's less steep than loading it into a truck bed. He proved at Harlan that can be a risky game.
You may already know some or all of this:
The 2wd and 4wd frames are different. The 4wd frames are fully boxed at the front. You can slide some rectangular tube in the front and weld it in though. People with 4x4 OBS trucks found that the Super Duties rode a lot nicer, because they had the front leaf shackle behind the axle instead of in front of it (like a YJ). Which is good news, you can pick up a reverse shackle kit and a pair of SD front leafs and that will get the axle in.
Then it's just transfer case, either divorced or swapping in a 4x4 E4OD, driveshafts, linkage, lifting the rear axle to match, etc. I had considered doing all of this to my white F350 and then realized it still wouldn't be worth anything when I was done