Thanks for the inputs. With the hose-reel, mine has to be either just upstream of the reel itself, or down by/within the pump.
With my previous rv's, the valve was right where the external hose connected to the inlet fitting, but I think it's different with the reel concept. I'm going to have to look further in the pump area too.
Just don't want it to be something I have to remove that big panel for
Hendrik - it's been a long time since you've been to Curry Hammock SP, maybe you need to stop in and crawl back there again to help me, like in your pics.
Failing all that, I'm just gonna use a plastic hose-plug I found, and forget about it.