Jesus wept! The size of those batteries, too! I use one 85AH leisure battery, and even the people with motor movers manage on two 110AH batteries. Most caravans here have "smart" chargers which vary charging rates to avoid too much plate damage on recharge. 500 watts at 12 volts (if the chargers were 100% efficient, which they aren't) is over 40 amps which (if the batteries would stand it, which they wont) would recharge a usual UK battery in between 2 and 3 hours.

Heating - propane or butane
'fridge - propane or butane
cooking - propane or butane
Water heater - propane or butane
Shower and water pump - 12v about 3 amps for about 5 minutes daily
Lights - I use low voltage flourescents mostly - about 1 amp for not more than 20 minutes daily: having reached falling down stage at festival, make tea and take it to bed, drink it and become unconscious.
Grottibotti - manual pump
Outside lights - candle lanterns
Control circuits - (water heater and fridge) about 0.1 amp continuous
Biggest current draw? If I run the cassette deck and turn up the power amp flat out - about 5 amps, but in real life I run the cassette deck or wireless quietly for not more than half an hour a day. I'm at a festival and want to be doing live music.

Aircon? My whole caravan cost me £250! It has however had the interior cupboards largely ripped out and fitted with guitar shelves (another £150) and a new 'fridge (another £180). Anyway I like the heat, although we don't get it as hot as you: but last time I was at the International Bar Association COnfrence in Singapore I was tending to annoy people by still wearing a 3-piece suit (not lightweight, either).

Broadstairs last year I needed a charge after 5 days of the 7. Others borrowed the Yamaha about every 2 days,and burned a tank of fuel each time. I've never needed the generator over a 2 or 3 day event, but it's nice to have it in case of need.