8 lug wheels are 8 lug wheels for all makes that I've come across with the exception of one....the newer super duties (when they went to their own body style as opposed to the same as the F-150) have a metric pattern. I don't know who's pocket (Weld, Cragar, American Racing, etc) has it's hand down, but someone is making some money because of it. If they are older Ford rims you'll be fine.
As for running the 38's....I think you know already that that is a foolish idea. The front is weak. There is no way around that fact. You're smart to go get some halfshafts now as the tripod style CV's are notoriously weak. Also, I would worry about the rear axle. If you have a full floating 10.5 inch 14 bolt it is as strong as a Dana 70 and a little shaving of the extra casting below the cover will give you clearance comparable to a Dana 60. My gut instinct is that you have semi floating "metric" 9.5 inch 14 bolt just like the 454 SS, 3/4 ton suburbans, etc had. While it is still tough, c-clips are the devil and parts for that axle will blow you away. The easy way to tell is to look at the hubs. If there is an axle flange with a bunch of bolts inside the lug pattern you have the 10.5 inch unit....a genuine keeper.
Now we need to move into gear ratios. You will likely have 3.08's, 3.54's, or 3.73's. I guess there is a remote chance you will have 4.11's if it was actually used for hauling. Find the tag on the door as it should say. No matter way those are kind of high gears for turning those tires. That's not to say it can't be done, but it will be noticable.
The transfer case is going to be a New Venture 241 model. This is a reasonably tough case with an excellent 2.72:1 low range. This is the same t-case that the Jeep Rubicon and the miltary Humvee base theirs off of. Again....a keeper.
You didn't say if the tranny was a manual or auto, but I'm just going to assume it was an auto. If that's the case I'm 90% sure it will be a 700R4. I guess it is possible that it is a 3 speed Turbo 400, but not likely. By 1992 most of the issues with the 700R4's lockup converter were taking care of. It's not the strongest tranny out there, but it has a deeper first gear ratio than a TH350 or TH400 and has an overdrive which is of course nice.
If you can get the truck for cheap, by all means jump on it. Wheel it until it breaks and start saving to do a solid axle swap. That's what I did on my toyota and haven't gone back since then. 36+ inches of combined travel can't be beat. It's amazing what a little extra wheelbase and all that travel can do. I walk circles around a lot of XJ Cherokees that I wheel with who have locked diffs in the rear and in some cases in the front. It bothers them that I run open-open most of the time (I do have a welded third member I swap in on occasion) and never have a problem. No tires in the air means no loss of traction.