If with AC on noise n vibration are not an issue, then without question USE WHAT YOU HAVE.
Carry lots of propane tanks. They are going to take up about double the space of gasoline tanks, but will not spill or smell either.
Is it worth $1,000 or so to take extra propane?
You only need it 2 hours per day then that will not be a huge use of propane anyway, unlike running it all night.
Buy a propane auto switchover hose/pigtail that lets you run the onboard tank plus an aux tank from the ground so you don't run out and have to run out and swap.
Also, for future, is your propane gen able to be converted to gasoline? If that suits your needs better then consider it. It is mostly all in the carb and should not be too complex to switch.