I have a 50amp receptacle that's powered by my 10k generator and I want to add a 30amp box so that my friend can plug his camper in too, I know how to do the wiring but will his camper have a problem ...
You can find out what leg powers the A/C by finding the circuit breaker and with the power off, ground one circuit breaker, then look for the leg that is grounded with a ohm meter.
The 10,000 watt generator should make about 90 amps at 120 volts, so if balanced perfectly, should be no problem powering both rigs. However it would be possible to overload one leg of the generator, so it is wise to figure out what leg your A/C is on.