I picked up my 1st travel trailer. I want to be able to run the A/C, TV and use appliances without any issues. The A/C is 13,500 BTU. The trailer is a 2016 Jayco Jay Flight SLX 267BHSW.
The smallest power wise that works for most 13.5k BTU A/C units is the Yamaha 2400w inverter genny. However, most people buy a pair of 2000w inverter generators, Honda/Yamaha/Champion and a parallel kit. They are easier to carry and you have the option of only taking one when you don't need A/C. The Champion 3100 is slightly louder, but a pretty good value.