Popeye -- The panel is 20 x 48. It sits on the ground, picnic table, or wherever else we can find a sun spot! It's not nearly as convenient as a roof mounted panel but it runs at full power for much of the day this way even when the trailer itself is sitting in the shade. (and I'm weird enough to actually enjoy adjusting it when we revisit the camp during different periods of the day!)
I've a full-width pull out storage bin that sits under the sofa at the front of the trailer...you know, the kind that is accessible from the outside of the trailer through doors on both sides? I pull the big bin out the opposite side which gives room for a tray mounted to the top of that compartment to tilt downward -- this upper tray holds the solar panel when not in use. I wish I had a picture -- this is way simpler than it sounds! Keeps the panel out of harms way really well though when it's not being used and I can still fill the storage bin up to full capacity.