Snakebite-
By the picture
in the brochure for your coach, you could mount a GPS using
RAM Mount components to the panel that holds the BATT BOOST switch. You can feed it 12V through the panel. Depending on the GPS you have, you may be able feed an audio output from it to the radio, to get the higher audio volume.
I did something like this for our current coach, and it works very well. I have also used the RAM Mount "cup-holder" for a less-permanent mounting solution in out former Class C. Putting the GPS in that position is off the line-of-sight through the windshield, but it had the advantage of being accessible by both the driver and navigator.