I use a 32" Sony LED back lit LCD. It's light
for it's size. I bungie it to the bed in transit and then hang it with wire (like a painting
or framed art) over the right rear window when I want to use it (or need to sleep on the bed!).
But I'm a huge movie guy, I full time and a little screen would be disappointing. I can and do watch some entertainment on my 13" laptop screen, 7" tablet screen etc. But LOVE having a nice high quality TV in the trailer. I think you could permanently mount it on the wall, but then that window would be worthless. And I also can put the 32" on a table and use it as a computer monitor when doing design or photography, you just reattach the table stand.
I can stream internet to it directly from my phone with it's hotspot feature. It does Amazon and Netflix movies right on the TV, plus lot's of other online entertainment. No need to boot a computer. There's even a camera and mic option for Skype on the TV. Play movies and images off USB media or over a local network. I can even watch stuff from my phone because it has an HDMI output, so I can see any android apps or media players on the big TV screen.
I just wish it was 12V DC!