Originally Posted by Steve L.
If I were to replace the city water inlet I'd go with a marine unit because they're generally more robust and weather resistant than RV stuff. I use a lot of stainless on my trailer. It's pricey but generally good stuff.
I agree with Steve 100%, I have done the same and use a number of marine fittings and items.
For the water fill I have used a marine deck fill. you will need to place a hose into the opening to fill the tank and not user friendly to bucket fill, but it will out last your trailer.