Looking for the fresh water tank access

[2 DA WDS]

I bought the See Level guage system for my 3 tanks. Last weekend I went looking for the fresh water tank. On my other 05 RE3 I could see waaayyyy back in the 'utility room' where the fresh water fill attached to the tank. In this 05 RE3 that is a couple months older all I can see is the fresh water fill disappearing through the back wall. So, last weekend I started to drop the underbelly to get to the area behind that wall and between the entry steps and fridge. I found insulation and a piece of plywood there where I expected to see the fresh water tank. I called Doubletree and after some discussion they decided that there is a bracket on the frame that will drop the plywood and expose the tank. Has anybody had any experience with this. If you have, how much of the tank can I get to from under there?

Thanks for any info.