I have had great success with EZ Anchors -- here is an example -- they are available at hardware stores:
EZ Anchors
Some tips: first, drill a pilot hole roughly the size of the core of the anchor. Use a Phillips screwdriver to screw them in. Whenever you are drilling into a wall in your trailer, make sure you use a piece of masking tape to mark the depth of the wall -- do not go through the outer wall of the trailer. Cut the anchor so that the tip does not hit the outer wall. Do not use an overly-wide screw when screwing into the hole in the middle of the anchor.
You do not need to find a stud for these anchors -- they work well in the foam behind the luan paneling.
Perhaps try these out in an inconspicuous area (under the sink??) until you get the hang of it.
Good luck!!