I went with the cheapest of the AirLift units -
AIR LIFT 25804 Air Shock Controller Kit https://www.amazon.com/dp/B000CFO05E..._cSF2xbTCB32VD
Mounted in the wet bay, where the left side fill was. Pulled power off of the converter (which is also in the bay) and routed the right side line across & used a 'T' to connect it in with the other. I've lost the ability to fill them independently, but frankly don't care. The analog gauge and controls are right there in the bay, easy to check and run every time I stop for gas.
Turned out to be a quick and inexpensive fix to an annoying task. Now I don't have to unpack the bays to check air, or run around to both sides, or dig out a pump and stow it when I'm done. I'll try to remember to snap a pic in daylight tomorrow.