We're at the FROG Rally and we had an opportunity to ask one of the techs how to access the cables behind the tv, and our tv (2014 Rockwood/Toshiba) is mounted on the wall like a picture frame with a 'keyhole' type mounting. By lifting up first, then away from the wall we were able to remove it from its mounting to access the cables behind.
Hope this helps!
Linda & Paul
2014 Rockwood Signature Ultralight 8292WS
2016 Ford F-150 XLT 4X4 Supercab,
3.5L V-6 Ecoboost