I don't have a CS but I have a 190 with an all electric fridge. We run the fridge the entire time that we are traveling. It goes on when we leave the house and it does not go off until we return home. I need that fridge for my meds and had it installed before I took delivery of the Roadtrek. It runs fine on our two coach batteries and when we hook up at a campground the 110 v takes over - and recharges our batteries at the same time. We have the Onan generator and it also will power the fridge and charge the batteries. You are correct about the engine generator. It is actually an large alternator that will recharge the batteries to full in two hours. There are now also solar options for all Roadtreks that will keep your batteries charged during the day. The A/C will only run off the grid with the ETrek's solar and power capacity (8 batteries) and it will do so for an estimated 9 hours - with no other drain on the batteries. (And that number may not be accurate.) Then the engine generator needs to be run to bring the batteries back up. The ETrek can be fitted with multiple power sources.
If you plan to boondock for more than a day then you are going to need to recharge your batteries at some point. If you plan to go in and out of campgrounds, the compressor all electric fridge will be fine with two batteries and regular recharges. The Roadtrek batteries charge while you drive on all models.
If you want more space inside, get a 210, have a compressor fridge installed (I suggest NovaKool as it fits the space with over 4 cuft inside), and have it optioned with solar panels and 4 AGM batteries, the Onan 2800 and the larger inverter.
Anyway, I had to have the all electric fridge for my meds and I do not need to be level to run it.