Our VT has the potable water filler next to the city water hookup just like you have mentioned. However, we have another potable water filler on the right rear of the trailer, too, just left of the tail light
. I wonder if the original VT had two fresh water tanks? Of course, none are left now so I can't just look. When we bought the VT in 2007, the PO had put in a large water tank in the space between the two rear benchseats (or in the space under the bed). We took that out to gain the storage space back. I assume the tank sat under the passenger side rear bench seat, but I don't know for sure. Any VT owners know?