The problem is the cheap 12VDC sockets you find at loacl auto parts stores are not very good design. You might want to look at the high quality marine style 12VDC sockets and matching plugs.
Also the USB PORTS are almost required for most of the kids stuff... You need to have a few of those in their area as well...
Check out BLUE SEA Marine quality 12VDC products. You might even may want to install a small 8-position 12VDC BLUE SEA fused sub panel. I do this for my ham radio type devices... This is fed by a large cable from the truck battery area and then you can add several smaller fused circuits from there for the various thing you want 12VDC power for.
All of this is available from BLUE SEA and when you find what you want always type the BLUE SEA PART number into AMAZON and purchase from them. Yo will get two day delivery and sometimes a discount if you are a big AMAZON user...
Roy Ken