In article ,
Bennett Price wrote:

Have you considered replacing the galvanized pipe at the shut off, where
you can unthread what is left of the iron and insert a short nipple plus
a dielectric union - or perhaps just a brass fixture, threaded at one
end and sized for a copper pipe at the other.

That would be ideal.

What's keeping me from doing it is a fear that if things go wrong there,
there's no where else to go (without help and $$).

If I start a little distal to that, I have some extra space to get
things right. That's why I figured I'd start at a joint, if that goes
wrong I'll have room to cut the pipe and try to thread what's left.

If, however, I get the first joint apart easily (I can dream, can't I?),
I may get brave and take it back to the shut off.

Thanks to everyone for their help. As always this group is a great
resource.

Mike