The generator is a 6000 watt Onan diesel model. It is more than enough for both A/Cs... but because both are starting at once, it is eating 120 locked rotor amps.
I wonder if there is a way to have one A/C just have the fan run while the other A/C starts up, then the second A/C would start its compressor. I also wonder if a hard start capacitor would help as well, as described above, but with both compressors firing up at once, I don't think even that would help.
Pianotuna is also right about generator exhaust... I'd consider a Gen-Turi kit since it gets the exhaust to disperse a lot better, and not around the coach.