You need to locate the studs in the wall and anchor into them. If your camper is aluminum or wood framed, it doesn't matter. Anchor into the studs in the wall. If you don't, you're just anchoring into a very thin outside skin that will strip out a hole in no time, and then you have a hole in your wall.
Make a very small pilot hole into the stud, then use putty around the hole to make it water tight. Then screw in the screw (or bolt) if you decide to go completely through the wall to the inside (which some do sometimes, if the bolt comes out inside a cabinet).
A word of advise though? You might want to rethink mounting in one spot, and might be better off leaving the television mobile. If you mount it on the side, you will be dealing with bright glare in the daylight. At night, after dark, it will work just fine. But if you watch television in daylight, you'll get nothing but glare. We have found setting up the television facing the trailer at the edge of the awning eliminates a lot of glare.
Another problem with mounting on the side of the RV? What happens if you find your campsite is not very level? The place where the television mounts could be way up high, or way down low? Your chairs may be down a hill, or up a hill from the side of the camper.
Leaving it mobile means you can put it anywhere.