I think it depends on what area you want to see from your camera, and the capabilities of the camera also.
When I installed side camera's on the Holiday Rambler we had, I temporarily added longer wires to the camera so that I could try the camera in different locations, both high and mid-height on the coach. I used several strips of masking tape to hold the camera in the various temporary locations.
Before I began the process of trying various locations for the camera, I thought I wanted them high up on the front side of the coach. I finally determined that the front side at the level of the bottom of the windshield was best for me. Of course, this location that I used may not be be the best for you and/or cameras.
Fred
Fred & Vicki
St. Augustine, Florida