I would use lithium ferrous batteries in preference to the AGM batteries, lighter and you get more useable Ah from them. If you haven't already bought the battery charger, there are a few good 40 amp and 50 amp units that will run easily of the generator. 300Ah of lithium would give you 2 full days and nights, the third day you would need to either drive or run the generator for 5 to 6 hrs, or 3hrs a day, which ever suited best.
I don't know if the sell to WA but appliances on line (Google search) have very good prices on fridges as well.
I can give you a few recomendations of chargers and inverters that I have bought from E Bay and had a good run out of if you like.
It will have to wait till the morning though, we get up a lot earlier than you lot
