My rear end

This is the last thing I had to check after Irene flooded the garage. I finally disassembled the rear suspension to free the pumpkin, and turned it over, a little water dribbled out with the oil. Does this mean I should take it apart and replace the bearing? How hard a job is this(for a cabinet maker)?

My vote is to fill it back up, drive it a little paying close attention to bearing noises. If all seems well, drain it back down and refill again after 100 miles or so. Replacing bearings in any rear end is tricky. There is preload and crush collars, wear patterns and all kinds of voodoo science in there. Really not that hard once you have the tools and you know what you're doing, but it's one of those things that give the people with the knowledge a God like mystique.

At a minimum, I would try turning the shafts with my fingers, to feel for any roughness. Probably I would also remove the center section to inspect inside, clean out any dirt that may have been carried along with the water.

While certainly not trivial, I'd say doing a diff is easier than a gearbox or engine, for example. You'll need some unusual but readily available tools (dial indicator, 1" micrometer, bearing separator, hydraulic press, 1/4" torque wrench etc) plus a few specials that you can easily make yourself (mostly brackets for holding things). Getting the contact pattern right is the most tedious part (assemble, check pattern, disassemble, change one shim, lather, rinse, repeat ad nausem) but with any luck your new bearings will match the old ones close enough that the original shim packs will be right.

Here's a few photos (not in order) of my Stag diff, just to give you some idea:
https://s258.photobucket.com/albums/hh260/TR3driver/Stag%20diff/