I have had good luck mounting a FLAT BACK BOARD to my trailer thin walls using MOLLY BOLTS in the four corners. Much like what was posted above.
I would be afraid not using a back board would allow the mounting screws to be pulled through the thin trailer walls... Finding the wall studs is great but not always possible. The MOLLY BOLTS spreads out behind the thin walls when installed to prevent being pulled through.
The added back board allows you to then mount the swivel design swing brackets using wood type screws you find in the TV SECTION of WALMART. Look for one that allows a quick disconnect or easy way to remove the HDTV when taking down. The bracket I found has the top rolls of slots where you can insert the screws in the back of the HDTV and slip into these slots taking the weight of the TV until you add the bottom roll of screws.. Once the bottom roll of screws are in place then you can tighten all the screws. Makes mounting the HDTV much easier for me using a two-inch short Phillips screwdriver....
The back board spreads out the weight distribution...
All photos from GOOGLE IMAGES
Roy Ken