RV Repair: trailer rebuild, wood studs, metal studs

Question
Am completely rebuilding a 1971 18' wood frame aluminum skinned Elkhart Traveler travel trailer and wonder if metal studs(the kind used in home construction, if dimensions are correct)can substitute wood to make lighter, without sacrificing structural integrity.   Plan to use 1/4" poplar plywood on interior walls and ceiling and 3/4" plywood for the floor. My guess is that I'll have to use wood studs for the floor, roof, and front and rear curved sections.  
I appreciate any feedback you can offer.

Answer
I'm not quite sure what your meaning is by completely rebuilding? Have you pulled the metal skin off the outside? If so what sort of metal skin was it? By that I mean was it one solid piece or was there several pieces to each side? The reason I ask is because by pulling the outside skin you will have access to the back of the paneling and 1/4" is pretty thick for walls and you should really use some kind of vinyl covered paneling that will stand up to the moisture that all coaches are exposed to. If you have pulled the metal you can remove any bad studs in the walls. By saying you are going to use 3/4" plywood for the floor one would assume that you have torn the coach down completely. If that is the case one thing to try and remember is that when you build the new walls make sure they are no bigger than the original walls in any way, because your metal won't stretch but it will trim. Coach manufactures gain most of their strength by laminating,(gluing) the paneling to the studs and then stapling the metal to the outside. The walls are actually about 1-1/2" thick. They build the floor and then set the walls on and screw to the floor. Then they set the roof on and secure it to the walls. When all 4 walls ant the roof section are together they are pretty strong. In doing it this way everything is glued and stapled and the metal acts as a shift stopper is the way I can say best. You want to make sure that everything the old walls had the new ones want to have as well unless you plan on replacing the metal on the exterior as well. Use elevator bolts to attach to your outriggers and everything should be fine. I would try and keep all extra metal out of the new construction as it adds weight. You should be putting enough metal in it with the pipe you use to pass wiring through all studs. As long as you keep in mind that strength comes from lamination you should do ok. One thing that comes to my mind is something someone told me years ago and that is they aren't a piano but just a RV. Oh and you will want to get some gimp to put where the walls meet the ceiling and other walls as well as the floor. This will cover the seams and make it so you won't need to put moulding in all the corners. Anything else that you might want to ask I will be here to try and answer for you. Thanks, Bill