Most of the on boards are Onan in the 4000 watt range. To run one AC and the rest of the unit you need about 4000 surge watts and 3000-3500 continuous watts of 120 volt power.
The on board units are pricey, I have a Honda EX4500 that I used for years but it's big and bulky. I just tried a combo I wish I had gone with 12 years ago when I started.
Dual Honda EU2000i generators with a parallel kit. If you don't need air conditioning, then run just one generator to save fuel, if you need AC then parallel them up for 4000 watts surge and 3200 continuous power which is plenty to run the AC and if you need the microwave, then use it.
There are many options, what I have above, a 3000 watt, 5500, 6500, Yamaha has the same basic options with only slight variances.
Having a toy hauler you can get one of the bigger units, they hold more fuel (They drink more too.), can roll them into a corner. They aren't easily stolen.
So there's many options. Many indeed.
2001 HO Cummins powered Dodge 2500
2014 Sierra 346RETS
Nights camped in 2014-28