Thanks for the video. My trailer has a pump installed but its plumbed into the old hand pump - the handle has been removed and it now comes on with a switch installed on the front of the counter. Your installation makes me wonder if I could somehow plumb it into the same tap as you are using so that I could again have a manual pump (in case I had no electrics). My question to you is are you still able to use your sink tap for city water at the same time?
I'll try and get some pictures posted of my installation which has the pump down by the water tank - it's a bit harder to access, granted but I don't lose all the storage under the seat.
I still have a 3/8 line connected to my hand pump with a backflow valve installed. Once the pump is primed I have backup water should my electrics fail.
This line is plumbed directly into my water tank.
I imagine you could put a T-connection in your line with an ON/OFF valve.
I can hook city water to an inlet, using a reducer, so I don't blow my lines.
With the city water hooked up the Shurflo pump usually won't kick in as there is always a constant pressure supplied by the city water hookup.