Yeah I found it odd that the fresh water fill was on the passenger side.
Seems to me you could just run a bypass that would go backwards over the pump with a single valve on it: open the valve and the pressure water from the system would flow backwards into the tank (only open the valve when the city water hookup is used). Could even plumb that into the winterizing port.
You could even use a 12V Solenoid Valve (see here: http://www.amazon.com/12V-Solenoid-V.../dp/B007R9U9BM
) and wire it up to a switch (so you wouldn't have to crack open a panel everytime you'd want to fill).