Nice neighbor to have Tom!

I was actually also thinking of having a wheeled cart with a 12V.

D-rings sound like the cheapest, quickest, simplest option. Will go for those.

Ironically, this trailer willl not be driven much around. Plans for it are for it to be driven twice or three times a year about 160km round trip.
The rest will be spent under a large roof (or outdoors) so I can drive it out to the flying area (less than 2 min drive) and have no dealings with loading and unloading planes more than is necessary. Its basically a "storage" trailer.

This implies, that I will not be charging it that often with the car, but I will certainly need a 110V plugin, outlets inside.

In doing a basic "needs" list, I came up with the following:
1. 110V AC Outlets inside, 2 or 3 boxes.
2. 110V AC charger for 12V batteries. I am planning on using a marine charger. Where I am is only 20 km from the pacific ocean.
3. Some sort of fault protection (clueless as to what is a good idea, also planning on searching for marine tailored stuff)
4. 12V deep cycle battery (Installed on the trailers front in a Box, easily removeable, with a tube entering the trailer with cables.
5. 12V Bus with banana plugs, points for alligator clips, lighter plugs.
6. 12V dome lights.
7. 12V fan. (It gets really hot where I fly)
8. 12V inverter (In case i need to use dremel, charge a computer, video camera, or use other 110V AC accesory at the field.)
9. 12V Line protection from the battery in case of overloads.