There are a few "diversion" loads that you could use. The most common would be heating water in your water heater. You can purchase a 12V (nominal) immersion rod heater for your water heater. Of course, different styles of water heater will require different parts. That way you have already hot water going into the evening, thus saving propane. You could do the same thing with a space heater, heating air instead of water, but this is very inefficient...though it is "free." Peltier junctions (google it!) can be used to cool your fridge contents (or heat something....) If you are really techy then a fresh was maker COULD be run (depending on howmuch power you have available) to replenish your fresh water tank from seawater.
Use your imagination...I am sure there are lots of other ideas floating around...how about Solar Coffee (electric machine/inverter/diversion load power)
I love solar!
Rich "The Wanderman"