Your projector platform is almost as important as your projector. It needs to be sturdy. Even a small movement from the wind at the projector will be magnified in the projection.
You want your projector to be easy to set up and sturdy so someone doesn’t knock it over while viewing your show. Consider a 2×2 foot piece of plywood with tripod like legs and a ceiling mount that hangs underneath. This will allow for fine tuning with a sturdy and adjustable set of legs. I tried 1″ PVC pipe as the legs in a setup like this but they proved too wobbly. Go for at least 1.5″ or 2″ if you try this route.
You could build your own enclosure too. This year I’m aiming for that. I’ve got a cemetery fence that runs along the front yard. I’m building two columns to hold a gate. The projector will be housed in one of the columns. This way I can make it (mostly) weather proof too.