I am not a big fan of using the 12VDC cigarette lighter type sockets. They are cheap in design and will get hot and burn out plugs and wiring...
What we do here is run a 120VAC extension cord drop from a 600WATT PSW Inverter that is installed within five feet of the main battery switch. One 120VAC drop goes to the Home Entertainment area and the other120VAC drop goes to the bedroom area. Then you just plug in your 120VAC small appliances to charge up things and run your home entertainment items just like when you are at regular camp grounds with electric.
All of the small devices gets their power from these two 120VAC emergency power drops.
I probably have way more capacity than I need but I started out with a 300WATT PSW Inverter, then went to a 400WATT and now have finally settled on a 600WATT PSW Inverter.
This fits into my camping off the power grid plans just fine...
Here is a typical trailer layout of how you install this. I have no installed cabling visible inside my trailer - all cables run inside WIREMODE or behind cabinets to get from Point A to Point B. The only thing visible is the 120VAC mulitple port mounted to a table top or up inside a cabinet...
I would suggest at least a battery bank of 220AHs capacity for when camping off the power grid. Most folks like to install the two 6VDC Golf cart Batteries which only cost around $90 each from SAMs Club or COSTCO. Also when campng off the power grid you really need to looking into smart mode charging techniques and a small generator to run your smart mode charger. With this you can return your batteries back up to their 90% charge state in just three hours time.
The problems we run into here on the East Side of the US is most public places has generator run time restrictions in place so you have to plan out your 120VAC and 12VDC items you want to run to make your batteries last until you are allowed to run the generator to recharge them.
Since you are in a POPUP you might be interested in my floorplan layout of my OFF-ROAD POPUP showing where these things are installed. Food for thought...
Roy Ken