My conversion project is possibly going to the extreme for structural integrity as I have been framing everything with Unistrut and other steel and I will be using self drilling self tapping screws to attach plywood. My experience from doing this on my first Crown was that I didn't get squeaks and rattles. The steel structures are incredibly strong. As for weight, Unistrut weighs 187 lbs per 100 feet. I purchased 30 10 ft lengths of strut for the project, adding in the angle iron and steel straps used in addition and the weight lost from removal of 26 or 28 bus seats at 40 lbs? each make the weight gain pretty small. I use the approach of do it correct the first time, and don't do it over. I can mount anything one would use in an RV and not worry about whether the framing is strong enough to support it. I will be tiling both the kitchen and bath and to assure that little or no oil canning is likely those walls to be tiled are to be as secure as possible. My approach provides multiple means to support plumbing and wiring also. My way is not the only way.
You could also glue everything.