The MacBook is going very well at home. There have been no problems at all, the Drobo remains accessible and BackBlaze is near the end of the initial backup. I am really happy. I have set up a first cron job on my Linux desktop to backup essential files to the MacBook once a day, so they can make their way up to BackBlaze.
I read one suggestion about putting it on a timer to exercise the battery. I bought one of these Woods Timers and installed it.
It works just fine. It turns power off to the MacBook for an hour at 4am and 4pm so it runs off the battery. That's been in place a couple of days now, and there have been no problems. I will check it on the weekend to see how low the battery gets after an hour without power, and then I might tweak it. Right now I am flying blind.