On a different bike tour I met a groups from G.O.A.T.S. (Get Out and Tour Someplace.) They had a very nice van with a well designed roof racking system. If you are still thinking of this you can find them at: http://www.goatscycling.com/

If you are persuing trailers, fork traps can be temporarily mounted on the floor or walls to secure bikes for transit.

Finally a backing tip I learned early in my trailer days is when backing place your hand at the bottom of the steering wheel. Move this hand in the direction you want the trailer to turn.

Good luck!