Finishing nails (brads) by their nature have very small heads. Used alone, they would not be sufficient for the permanent installation of paneling in a trailer. They would, however, work well to hold the paneling in place, while some construction adhesive, applied between the paneling and furring strips dried.

Flat head stainless sheet metal screws, would be a good choice to attach the furring strips. If you were able to find a source of the longer aluminum pop type rivets used by the RV folks, and a pneumatic gun, that would work as well. They have washers that fit under the tail end of a pop rivet, that expands the surface area significantly. It allows a higher grip strength and lessens the chance of a pull out.

BOL  Gard

kjstewart
 You're welcome.

There is another matter you may want to consider; the rigidity of the paneling you're planning to install. If the spacing between the studs is wide enough, you will experience some flexation in the paneling if you push on it. The conversion company would lessen this situation with the additional installation of plywood. It would be similar to a sub floor underneath your finish flooring.

You could perform a test to see if you will be satisfied with only the final panel installation. Get a piece of scrap paneling as wide as the studs and temporarily tape it in place. Remember that some areas will be covered with cabinetry, trim pieces, lighting fixtures etc. Other than ceilings, there are few places in a LQ that include large open areas of paneling. You can feel if will work for you, and you can then get a good idea if it is applicable to your desired outcome.

BOL  Gard