I set up a backup to portable hard drive to run tonight so I could park it at the office as an off-site backup. It worked, except for two little details:
1. I should have run it from the master admin account so it could access the data files on both my and
starmalachite's accounts. The log had a long list of "could not access file..." complaints.
2. Turning on the encryption would probably be a good idea.
The process seems to run about four hours, so I can try again tonight and have it ready in the morning.