Wow! I've been thinking of doing something like this myself, but unlike you, probably never will. Over all, looks like a great well thought out process.
Biggest thing I like is keeping part of the bed in the main area with putting the cabinets under for extra storage. I'll be curious to see the end results.
When you are figuring where things go, don't forget to think about how to repair something. Even things like grey tanks may break after time or in mishaps. While removing a shower stall may be acceptable to replace a grey tank, it would be terrrible to have to rebuild walls in the process.
For the aluminum roof, there needs to be a barrier between the plywood and metal. There tends to be a reaction to between the two and may cause pitting at the contact point. They make a carboard type material for this purpose.
Nice to hear the DW is doing the drafting making this a true team effort. Would love to see some of her drawings.
