As far as panels I use these, watch the video to understand see: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...geName=STRK:MEW
A charge controller should always be used.
I prefer not to mount panels to trailers...I do not like to penetrate fiberglass hulls because of leaks
, next the trailer owner usually seeks shade, which is counter intuitive to solar
operation so I build a wood case for the panel, one that opens up so the panel can be set into the direct sun light
moving it around from time to time to keep it in the sun...the trailer can stay in the shade, I modify a 50 extension cord to run to the panel...I use a cigarette lighter plug into a female socket to feed the trailer the power, on the other side of the socket inside the hull is the charge controller.
When traveling I close the case and put it away.
Northern Tool makes a factory version of lesser quality and capacity but they are simple and work. This unit will not require a load controller.
Happy Camping, safe trails.