Westend, thanks for the info, I will go over your build carefully. I plan to make some significant changes to the floor plan which will end up moving the shower and toilet (hence the black and grey water tanks), I'm doing this to open up the main living area more.
Sounds like you have a good handle on it. A "blank canvas" is easier to fill.
If you need replacement jalousie windows, I still have a stack of them. Free for shipping cost. I found nothing good enough to keep them. I'm up here in MN, though, so a Desert guy may need them. What I do is open a slider. If it's about to rain or a downpour, I can throw a towel down on the sill to catch any drips. A good venting system (vent shrouds)and vent fan obviates the circulation issues. YMMV.
If you have the wherewithal to build a good composite panel, that would be definite time saver and add some integrity. Make it just a bit deeper than 1 1/2", if possible. A CNC machine that could handle the dimensions of a long wall would be ideal. I see some of the factories using them and it is obvious that carving out a raceway or box location is superior. IIRC, Lance RV has a video of their CNC machine posted.
There is a member here (*memory fails*) that scratch built a custom toy hauler. His integration of the mechanicals was above brilliant. If you can find the reference, it's worth a look.
