I have a AMC 20 under mine with one piece axles and a Detroit locker. I haven't regeared it yet, but plan to in the future. Not sure what your set up is, but I use to run an AMC 20, 1 pieces and 3:31's with a trac loc in it. Never broke anything and that was abused at it worst, lol. I also have a Dana 44 out back, that I have been saving to swap it if I ever snap anything. I think the AMC 20 built correctly is just as good as the Dana 44, some may differ though on my thinking.
You need to figure out your maximum price and put a cap on how much you want to spend, if you are doing the work yourself or having a mechanic do it.
Axles will cost you say $400, new brakes $100, Gears about $550 for front and rear, seals and bearings for the front ?? then labor cost ???
If you know what your gears are, try to find a matching Dana 30 and Dana 44 out of an 86 CJ7, most were made in the later part of the year. If you can live with your gearing, then I would just go the 1 piece axles and do the brakes and then see where you are at.
I would post here in the wanted section, Craigslist or Ebay. You may also try a salvage yard or even buy a parts rig to get what you need, swap it and resell it or keep it. Good luck.
85' CJ7 Laredo, 383 GM, Turbo 350, NP 203. SOA, 2" frame lift, 34" TSL swampers, Dana 30 open, AMC 20 w/ detroit locker, 4:10's, 1 Piece Mosers, 35" boggers to abuse when needed.