Here is a link to a thread with our current set-up, we had this built becuase the previous set-up we had worked really well for us, and we made a few modifications but followed the same pattern on the trailer.
One thing important to me is to be able to have shade for my dogs while we are parked or hanging out. Otherwise it keep moving the trailer to shade the dogs from the sun, one we have now we park directly facing the sun andth edogs are good for several hours if neccesary, but protection from elements even whe n dricving 60 mph hour down the highway is neccesary
http://www.easttexashogdoggers.com/forum/index.php?topic=10372.0