Also - cooking. Do you cook with propane? Is your boat propane tank pretty full? We found a 17 lb tank would last about 6 weeks. Baking in the oven used propane quicker so avoid that if supply is an issue.
In a pinch find a BBQ tank from home (yours or other folks) and hook up to your boat's...
Sorry you were hit. But a boat is a great escape shelter compared to living in a FEMA trailer.
Yes running the engine just a tick over idle about 1 hr / day is typical. Really depends on how big the box is, how well insulated, how hot it is, etc etc.
I second the idea of about a 100 W solar...