Installing a paddle fan in an RV offers a number of challenges such as cutting a hole without damaging existing wiring, supporting the weight of the fan and running new wires through the ceiling and wall for a new switch.
I've found a small router to be the best tool to safely cut a hole in the ceiling or wall of an RV. With a router you can precisely control the depth of cut so as to avoid hitting a wire or something else just below the wallboard surface. In this case, once I knew there were no wires or structural ribs I continued to cut deeper so I could add a 3/4" plywood mounting plate to carry the weight of the fan (a messy and dusty job for sure!). I also put (2) 5", #10 screws up through the roof so we would never have to worry about the fan falling down on our bed. Once this was done, installing the motor and fan blades was easy. Then, the moment of truth; I added 12 volt power with the help of some alligator clips and flipped the switch. Ah bliss, a beautiful whoosh of clean, dry Montana air, right down on our bed. Tomorrow I'll finish finish installing the wall switch before we head for Glacier National Park.