[pairodice]

We did figure out, after much trial and error, what the water valves do.  There is one that is a drain for the tank on the left side, one for filling the tank through the main filter, one for allowing city water directly into the coach (on right as I recall) that basically closes off the line to the tank (I may have these two backwards).  I will have to build a schematic of the system...  I believe that there are two Everpure filters that connect to the sink and refrigerator filtered water systems.  There is also a main water filter into which I installed a carbon filter in and that made the water taste better (or maybe it was just psychological...). 
I bought an RO system by Whirlpool from Lowes last week but have not installed it.  After reading some articles I may just opt for several filters (10, 5, 1, .04 and a UV light) to kill all the bad junk in the tank and city water systems. 
We are getting a new instant hot water system along with a new counter top combined hot/cold faucet from Amazon.  Will let you know how it works out... we just need to change out the microwave and stovetop and we would have a completely new kitchen! (ain't gonna happen).  Maybe we will change out the sink next but that may be a Newell/Foretravel job (whoever is closer)...