In hindsite I wondered if it would have been possible to remove the front of the cabinet instead of trying to work in the small cubby space. We are in Alameda if more information is needed. Good luck with your project, I'm sure you will enjoy the improvement.
Thanks for all the helpful information (and offer for more info if needed)! I have thought about removing the front panel of the cabinet, but that introduces its own set of complications... This will be a winter project after our last fall camping trips are in the books. I'm going to try and see if I can do it with the sink in place, but I suspect we will have the same problem removing the split brass nut. I have been happy with most of the components of the camper, but the factory faucet is one glaring exception. It seemed like it was ready to break when it was new, and after a little over a year it is leaking and showing signs of impending failure.