Recommend new, standard , RG-6 coax on the outside thats exposed to the weather. Here are some antenna mounts ,
http://www.ronard.com/909911.html ,
http://www.ronard.com/34424560.html. Do not have the antenna hugging the trailer , it is a good idea to have the antenna a minimum of 3 feet higher then the highest point of the trailer. Mount the antenna in a way that is Strong and Sturdy.