Some of my thoughts:
If you have steel behind the wall a magnet will find it---use a stud finder to locate wood . If your studs are too thin or they do not line up well with the mount---then you can add a sturdy piece of trimmed (for looks) plywood between two verticle studs with screws and mount onto the added ply. You can spread the forces by gluing the ply as well. It will be permanent then so decide carefully.
I found a steel cross brace in mine and it was not wide enough to fit the mount but by putting the screws in the top holes of the mount into the brace it was plenty strong enough to handle the light TV---the bottom screws are in for looks and a bit of added security. In about 7000 miles of travel all is well.
Good luck and Happy thanksgiving------------------
I do all my own stunts
03 Dolphin LX 6355, Workhorse W22, 8.1 vortec, 04 CR-V, Blue Ox, Brake Pro----Norm, Barb and
Doc(He's a PhD)