I like the solution a friend of mine used. He had a large picture window so he installed the projector inside and used an
electric screen with dual purpose front/rear projection screen material just inside the window. They could close the drapes and watch movies indoors as front projection or open the drapes, using them as masking, and watch rear projected movies outdoors. An RF wireless remote let them control it all from inside or outside, including the image reverse required on the projector for rear projection.