Want to test AC before heading south - no 30a service.

We do this often on a 20amp service from family and friends garages. Works out fine. It will trip if we put the hot water on electric or try the microwave or coffee pot. We've learned to manage just fine. We don't turn off the other breakers with 20amp service, but we do when using our 2400 generator. The most surprising draw in our camper is the convertor that charges the battery.