Welcome to the forum and irv2.
The best route you can make is to go down through floor and either through your lower compartments or run along the chassis rails with the other wiring in the "C" channel rails than up through the "A" channel beside the windshield.
The cover will come off.
Here is a Brochure and Owners Guide for you.----what year is your coach????
Here is info on your 12v battery system
and 12v wiring & fuse locations
In my signature below are three links that will relate to your Newmar.
In QT's # 3
look for the tv to LCD Section and PDR John has info on HDMI OPTIONS you maybe could go wireless.