Framing in Rv are much lighter and often not where we might think normal in houses. Finding them is critical for my thinking on mounting shades, etc. that get a pretty good workout as we lift/lower them. You are correct to look for real wood but how to find it is pretty tough at times. How are you on the old " knock and listen" thing? If I can't find it by pressing on the wall or listen for the hollow sound to change, I go with drilling or using an existing hole and running a wire like #12 electrical in to feel around. Sometimes the wall is solid with foamboard and I can only drill a few times and hope to find good wood.
Another, more modern method is the stud finders which use electronics to sense the density of the wall as they can "see" wires, pipes and such. Pretty expensive for one time use, though.
This might give you a good shot: