RV's and outdoor speakers?

Anyone have experience with RV's and outdoor speakers? Recently bought a 27ft Cl C and will be having a pretty good radio (carry Sirius) and amp installed. My brother wants to have a set of outdoor speakers powered by the radio for when we sit outside. All intelligent thoughts and ideas appreciated. Name some make and models if you want. The speakers would not be permanently placed to the side of the rv but maybe?? the mounts would be. Also the speakers don't have to be permanently attached to the radio, they could be connected to a plug coming from the rear of the stereo???? Anyway.....