Great, I will put together another album on flickr with everything I have. I used Google Sketchup to plan it out, so there should be dimensions there. I reused a lot of what was already present. I believe I used 2 sheets of 3/4" plywood to build the boxes. It was the 'cabinet grade' multiply stuff from HD rather than regular construction or floor grade. It's outer layer was light luann rather than fir/pine.
To instill more confidence in you, I don't remember having to disconnect any of the fluid or electrical systems other than removing the heater ducts temporarily until I could hook them up to the new openings. I did improve some things, however. I made a much stronger/secure box for the the shore electrical cord, insulating it from being near any fluid conduit. You will see in the pix.