The only foolproof way I know to do this is to beef-up your trailer with smart-mode charging, go green everywhere you can like using LED lights, think of all the things you want to run from 120VAC and then purchase an INVERTER to run those 120VAC items, think of all the 12VDC items you want to run and increase your battery capacity to run these items including the Inverter. Your battery capacity must be planned out to only drop to its 50% charge state in the one day/night battery run.
Then your game plane is to run all of these 120VAC and 12VDC toys for just one day/night battery run camping off the power the grid. The neighbor campers don't hear a thing coming from your trailer at night. Then at 8AM the next morning when allowed, run your 2KW Honda "QUIET" generator with the trailer 30AMP SHore Power Cable connected to the generator which will allow your on-board smart mode converter/charger re-charge your battery bank back up to its 90% charger state. This will only take three hours of generator run time which should fit into almost any camp ground generator run time restrictions.
You can do a good two weeks of these 50% to 90% charge state cycles on your battery bank before you have to do a full 100% charge otherwise you will start doing harm to your batteries..
We have been doing this method of living off the power grid and can run all of our toys except the Air Conditioner and High Wattage Microwave. Most everything works fine...
This would be a VERY FOOLPROOF method for keeping your CPAP going as you need it... Being a medical thing I don't think I would go on "Try this maybe it will work for you"...
We have been camping off the power grid using this method for a few years now and are very successful about it.
It does take some planning however...
Just my thoughts
Roy Ken