Cool project, maddogruff.
You may want to replace the inner frame rails with something a little more substantial while you have it apart, I'm sure you've noticed how thin and weak (and probably bent) they are.
If you support the transmission shaft by the inner disc, you can press or drive the disc, gear, and inner races off all at once by pressing on or driving down the end of the shaft, then flip it over and do the other end. My press won't set up to hold the shaft with the discs installed, so I use a pair of jack stands with some 3/4" square tubes spanning across them. There's just enough room to suspend the end with the driven clutch. A big brass drift doesn't mar up the end of the shaft when driving it out. I think all the bearings for that unit are still available from Motion Industries.
Good Luck!
Stuck in the seventies- not in the swamp.
(6) Attex, a Hustler, a Super Swamp Fox, (2) Tricarts, (3) Tri-sports, a Sno-co trike, 3 Dunecycles, and a Starcraft! ...so far