I'd rate it at least "3 wrenches", maybe 4. You'll need some special tools, but you can get by with ones that are either inexpensive or easy to fabricate. The book calls for a few more that are unobtanium, but they are not essential.
The main "missing" tool is the pinion depth setting tool, as without it you will have to do trial assemblies to check the tooth pattern & preload, then pull the bearings back off to change the shim packs and try again. But if you are lucky, you can use the same thickness of shim packs in each location and the tooth pattern will be good. (Don't try to reuse the shims, though, as the originals will likely get damaged during the disassembly process.) I got burned, though, as the new input bearing was quite a bit different than the old one, and it took me 10 or 12 tries to get the preload right. That shouldn't be an issue for you though, assuming you keep the original collapsible spacer (which also has to be replaced every time).
The "case spreader" also turns out to be non-essential, as you can just pry the carrier in and out of the case. Takes a fair amount of force, but it works. You can see some photos of the process at
https://s258.photobucket.com/albums/hh260/TR3driver/Stag%20diff/