Unless you are really planning on running BOTH A/C units, a generator that big is OVERKILL ! Plus, it will drink a lot of gas !!
There are a lot of nice portable inverter generators to choose from on the 3000-4000 watt range. They will only run 1 A/C, but they are A) less expensive, B) use less fuel and C) QUIET !
The question is, where would you mount a permanent or portable generator ? A portable can just be thrown in with your toys (lashed down, of course) and pulled out first when you arrive at your destination.
Securing your generator (lock and chain) are a MUST ! If you are going to be gone all day, you might want to consider turn it off and putting it back inside and then locking the hauler. Out of site, out of temptation !