We just spent 30 hours on the AMHS ferry Matanuska traveling from Wrangell to Juneau with stops at Petersburg, Kake, and Sitka. The trip was absolutely beautiful including narrow channels too small for cruise ships, glaciers, and whales. We had four hours on Sitka for a quick guided tour of the town and dinner and arrived in Juneau at 4:30AM this morning. We had cabins for both nights and really enjoyed the trip.
An update on residential refrigerators. Our Samsung AC-197, which has it's own inverter, was on batteries for 30 hours and the battery voltage was still 12.2 volts (under load) when I went down to the car deck this morning. Yesterday afternoon after 20 hours or so the voltage was 12.4. Our 12 pounds of frozen halibut was still solid as a rock!
With our four Trojan T-145s we could easily go a couple of days if necessary.