While the mirror mount is a great idea, it's a bit tough for the Bifocal/trifocal drivers. I like the location I chose for these reasons:
1) It is at normal view height - no looking up or down, just a tad bit to the left
2) It is easily reachable - no stretching or bending
3) Minimal obstruction of the windshield...
Some points to consider.
I'm planning on moving the backup camera monitor up and back so it no longer obscures the windshield as well, and is easier to reach. Not that it needs fiddled with as a GPS does, however.
We have a rear window that I'd like to install a Fresnel lens, and put a good old-fashioned mirror back on the windshield so I can glance back into the coach (what was that crash?) or through the Fresnel to watch traffic.
There's many options, but none that are perfect for everyone.