You may also want to get a new Shur-Flo city water inlet to replace your old unit. Ours was leaking very badly, so I ordered a new one on the web. Works great now with no leaks
when hooked to city water.
Since we try to find city-water sites whenever possible, I made basically the same setup you have in the diagram, but set it up externally for some trips. I put the water tank on a wheeled dolly and fill it up at a camp faucet. Then, I use snap hose fittings and put it together, hooking up to the city-water inlet on the VT. Plug it in and it's ready to go! As noted, small leaks
do cause the pump to cycle once in a while, so I check those fittings on the external hoses regularly. I haven't put in an external switch yet, but probably will so that I can turn off the power to the pump from inside the trailer when we don't need it pressurizing the system. This has been much easier for us than hauling water jugs into the trailer at dry sites. Plus we can still use the hot water heater and regular faucets.