renogy makes some nice folding portable panels, go for what you can store and afford, and all the portable panels I've seen have a PWM controller ON the panel you must keep the cable from the panel to the trailer as short as possible or charging current will drop like a rock. If you want a run longer than the cable with the panel remove the controller from the panel and mount it in the RV and run #12 or #10 wire from the panel to the controller.
I have 3 renogy 160W portable panels and a MPPT controller, give us all the solar we need.