Though I had done the procedure many times on multiple bay window busses,  I
had much more difficulty when I replaced all four rear joints and boots on my
'87 Syncro.  The joints were extremely tight-fitting onto the axle shafts and
I had a hell of a time removing them with the axles in a vise.  I ended up
having a local shop install the new joints with a press, and he even
commented that it was difficult.  Based on that, I would not think trying to
remove the inner joint with the rear axle still attached at the outer end is
a good idea.  Not that I won't attempt to do that very thing to replace my
inner front boot...
-chris