[wingnut60]

Don't have one yet, but doing paperwork on a '15 RSSA with the res fridge. With the 4 batteries I don't think you will have a lot of problems, especially with the gen on board.
Now, if you are going to do a lot of dry-camping, that changes things--but for driving from CG to CG, shouldn't have problem. I think you should have the 2 optional batteries dedicated to the fridge, and no other items on the inverter unless you want other 110volt items usuable without a hookup.
If you get the amp draw of the appliances you want to run, you can do the math on the amp-hours available from the 2 (4) batteries to get an idea of how much you can do off the inverter. Don't forget, the inverter itself takes some power.
Be interested in the answers you get--don't forget the Thor Owners forums to check for help there.
And welcome to the forum.
Joe