A couple of people on here hit on what we think was the solution --
the battery.

Apparently, although not old, it had been discharged too many times
recently. We swapped the battery out today and then took it on a 2.7
hour ride. Everything worked perfectly.

So, although we don't know why the rebuilt alternator gave out so soon
after installation -- the ongoing problem after replacing it the
second time was the battery.

Thanks for all the suggestions guys...


Chuck