Having the spare inside in a dropped floor is a great idea. There would be some additional storage, for items you may not need all the time, and to get at them you'd only have to lift the mattress. After a quick conversation with the wife, she reminded me that having the extra space in the 10 foot tear would accommodate our derpy dogs if needed, so I'm back at the drawing board with the original trailer modifications. I'm planning on installing a Pet*Cool for heat/AC, and was also toying around with the idea of a raised deck to run the air return and some of the electrical. I see that most people wire their tears by going over the top. Has anyone who has wired some underneath have any comments. I was thinking that for some of the lights, and electrical to the galley could be routed in the raised floor, while other things like the fantastic fan, and trailer lights could be routed above.
Here is a sketchup of the sidewall sitting on the deck, and raised flooring, or at least this is how I see it in my head. This would be different than the original ATMA Travelear in the sense that it would be 2 1/4" taller, as it would be sitting on a recessed raised desk. If I didn't do it this way, I might run into clearance problems with the torsion axle. Again, thoughts are appreciated.

