IB,
You have a few good options.
Cheap, fast and simple
All of what you mention can be charged from a USB power outlet. Get a multi USB charger and stick it to some nearby paneling and run an extension to an existing receptacle. The kiddos will have to supply a USB charging cord.
You can get a receptacle with USB charging ports to make things more simple. Put is somewhere that devices can sit while charging. Or, just put the multi USB there. This is what I do for guests.
Fast and more durable
Get wiremold at a big box and stick it to the paneling. Run Marine (Stranded) romex and use compression terminals as the typical receptacles and will not like stranded wire. (You need the stranded so it survives the vibration. Use a 15 amp breaker for 14AWG wire.
Best and most difficult, but cleanest.
Cut into the panel and get an "Old Work" box that will clamp into the paneling. Otherwise this is the same as above.
Nothing there that you can't do safely.
Matt
Matt & Mary Colie
A sailor, his bride and their black dogs (one dear dog is waiting for us at the bridge) going to see some dry places that have Geocaches in a coach made the year we married.