Do you want to remove the driveshaft, which is totally enclosed within the torque tube (and does not get painted) or do you want to remove the torque tube (the cylindrical thingie that goes from the trans to the differential)? I suspect the latter.
It’s not difficult, but it’s not trivial, to remove the torque tube. It cannot practically be done with the assembly installed in the car, nor can reinstallation practically be done by one person. You need to jack up the car, disconnect service and emergency brake rods, remove the clamshell (the two piece cover over the universal joint, which is a PITA job all of its own), drop the rear axle assembly down and out of the frame cross member, then pull the whole shebang backwards and out. You then loosen and remove the speedo drive gear, remove the large bolt holding the two rear radius rods to the torque tube, remove the six bolts holding the torque tube to the banjo, and pull the torque tube out. (There might be a retaining ring in there somewhere, I don’t remember for certain).
Reinstallation is the reverse, with new gaskets all around, but is complicated by needing to align the driveshaft back into the universal joint.
To my mind - out of sight, out of mind. I would only consider painting it if I had the rear end removed for some other reason.
