I plan on doing the same thing when I take delivery of my 23RLSW. The TV will have to sit partially on the outside of the opening. How far depends on how thick the TV is and the contour of the backside.
This is the TV mount I have on order.
Master Mount Locking Cantilever Mount, Small - McNaughton 94139 - TV Accessories - Camping World
It articulates and locks in place. My TV opening is not accessible from the side if I need to remove it, so this is the best way to be able to access the back. Just pull the locking chain to unlock and swivel and gain access to the rear.
I'm going to have to take careful measurements on how to mount it. I may have to build out where the arm mounts to get the TV to sit flush against the opening and get it to lock.
I plan to use some foam gasket material around the edge of the opening also to keep wear and squeaks to a minimum. My mounting is critical because if you look at my floor plan, the dinette slide comes in along the TV mounting opening.
The most I can stick out is about 3". I'm not sure what your TV mounting area is like and how involved you will be with the installation. My TV opening is 32" wide x 23 1/4" high and 39" diagonal. I measured this on a unit at the dealer.
I bought a 40" Samsung to put in. This will be the 1st mod I do. It's worth it to me to do all this work and planning for the larger TV.
There are other locking TV mounts out there just google for them. The mount I'm using is a Master mount 404L. My TV has a VESA mounting pattern of 200mm x 200mm. Make sure the mount you get fits the mounting pattern of the TV you buy.
Here is another type I was thinking about
TV Brackets / Medium Double Swing TV Bracket - LW Engineering
These locking mounts aren't cheap but this is the only type I can use. Wireman