Inverter usage while underway

I did find out that the refrigerator takes 2.7a when running on AC power, so p=2.7(i)* 120 (v) = ~325 watts , not sure if that is continuous. I am in the process of installing 12v power monitor metering, so i'll get a better understanding of the actual numbers. I also just did the math and for a continuous 325 watt i should get about 2hrs from the battery. I intend to use propane when stationary and use the inverter while underway for safety. I also will not use air conditioning or the microwave while using inverter. Hot water is propane only at this time. (Easier for me to plug shore line into inverter output and switch off devices too large to run at this time).

So it seems that, from all of your responses, that I can use the inverter powered by the vehicle alternator without draining the battery to critical levels while underway. Yes?