When I first started using a regulator, I put it on the trailer end of the hose. Then I camped at a campground where the pressure was so high it blew my hose. After than, the regulator went on the spigot end.
I like the idea of keeping the fresh water tank full even when you have a water hookup. I think I'm gonna start doing that. Once, years ago, before I had an RV, I was attending an event at a children's summer camp, and their well system blew up. It eventually required them to dig up a hundred feet of water main, and took 3 days to fix. Remembering how things got that week, I believe the full fresh tank idea is a winner. You know, just in case. Don't forget to empty and refill it frequently, though.