We used to have a Coachmen Catalina 20RD (right floor plan). Not sure which model you have - 1860BH as in floor plan below? I spent a lot of time figuring out how and where to mount a TV in our Catalina to be able to flip the TV 180 degrees and what I did is in the photos below.
The TV was a Sharp Acquos 18" with built-in DVD player. I mounted the TV on the end of the upper kitchen cabinet next to the entry door. That was the only location I could make work and be able to watch TV from either the bed (very important, lol) or the dinette and to do that, the TV could not be much more than the depth of the upper cabinet, 18". The 18" TV was not to bad for viewing and I have a feeling that anything larger may be too big for that size of trailer plus perhaps making it harder to find a spot to mount.
I used an articulating mount and to get it to fold back against the cabinet plus being able to swing out to be seen from the dinette, I had to use an articulating mount with unequal length arms. The unequal arm length is critical to make this work. After much checking around, I bought this mount from Videosecu
Videosecu articulating mount. I had to cut down the size of the mounting plate on the end of the arm as it was way too big for the rear of the TV. Very nice and solid mount (some are really flimsy). I bolted the mount through the end wall of the cabinet and then attached the end wall of the cabinet to two roof trusses (inside microwave cabinet) to make sure nothing would come loose in transit.
I used velcro to secure the TV in place while in transit. I removed the single receptacle for the microwave (in cabinet) and replaced it with a duplex for the TV rather than connecting to a nearby receptacle on kitchen counter.
The most time consuming part of all of this was running a co-ax cable from the very rear of the trailer to behind the microwave. I used many access points on the ceiling like the holes behind pancake lights (had to enlarge a bit); speakers; removed bezels on skylight and roof vents; etc. I had to cut a few small holes in the ceiling in hidden spots inside cabinets. Used an electricians fish tape, coat hanger wire and a single piece of #14 ga.wire to pull the co-ax through the ceiling cavity.
If you need to mount the TV directly on an outside or interior wall with luan plywood, you have to secure it somehow to studs (like Westend above) or something else equally secure. Our 18" TV + mount was 16 lbs total. There are some locking articulatings mounts (Mor/ryde for ex.), but they may not work if the arms are equal length.
I would suggest reading online reviews of TVs. Speakers are typically on the rear of TVs now to reduce height/width and the sound quality of sometimes isn't that great.
FWIW, to be able to comfortably watch TV sitting up in bed, we bought a couple of wedge pillows, 24x24x10". There was no place to store them at night though and usually ended in the shower. You'll also note a holder for the remote, keys & BBQ lighter below the TV I made.
We only kept the Catalina for a year before selling it to BIL who got the benefit of this and a bunch of other mods. He calls every once in a while just to say how much he likes the trailer and the mods.... :(