I attached a 100 watt flexible panel to my roof with silicone, and it works great. I couldn't remove it from my last rig, so I had to sell it with the panel. I'm willing to bet that it would work with any panel. Just put a good bead all the way around, and let it set for a couple of days before driving. I'm not fancy, so I ran flexible electric conduit down the front of my trailer to the battery box. I can upgrade cables if I need to. Once I changed out my lights to LEDs off eBay, and got a monitor, I realize we only run the battery down about 10% to 20% each evening if we aren't using the fans a lot. I take a 20 watt portable panel so I can place it in the sun if needed, but in the Southwest, we always get enough sun to charge the batteries.
2009 Roo 21ss + 2007 Superduty 6.0