The problem is switching from one to the other HOT, by that I mean that some of the devices in your RV do not take kindly to power flickers, and this is what will happen when the transfer switch transfers.
If heavy current is flowing, there will be arching on the contacts in the transfer swtich, this can weld them in one or the other position and leave you in the dark.. Air conditioners the compressor can stop and then try to restart with a full head of pressure (They are not designed to do this)
Solution, turn off A/C.s water heater and such (other big loads) turn off main breaker, wait 2 mintues, start generator, wait one more minute and turn everythign back on in the reverse order of turn off.
Same when you shut down,, Same proecdure save for "Turn off" generator. (You can do that soon as you trip the main breaker) wait 3 full minutes from OFF to ON on the main breaker.