I know you are anxious and you want everything just right and to be able to use it shortly after you take delivery. The dealer is not versed in AV installation and won't be much help.
Here's a thought: wait until you take delivery to really look at it. Then decide what kind of mounting system will work the best.
Monoprice has about the best selection of mounts you will find. Don't just seach on TV mounts, use other search terms like "monitor stand", "monitor mount", etc. For moving the TV in and out give them a call and see what they can recommend. I bet they have a solution. Great prices and very good quality merchandise as well.
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Chuck
2013 Jayco Jayfeather X20 E (sold)
2016 Chevy Silverado LTZ 2 Z71 Crew Cab (sold, and dearly missed)