I still don't get why you have to stop driving to start the generator. Don't you have a switch on the dash?
As the the A/C question, I think it depends on your EMS. I trust mine not to let the loads come on until the generator is up to full power. When I (or the AGS) start the genny, I can watch the lights on the panel come on progressively, showing the power available for loads. In hot weather driving, I have left the thermostat set for AC (usually just on the front zone) and flipped on the genny when it gets too hot, with no problem whatsoever. But my rig is not yours.