Hi Deb, I had to replace the city water inlet on our 1981 Bigfoot
17 just last year. It was easier than I had hoped: it was just threaded on to a pipe behind it, and was all accessible from the outside. You'll probably want two wrenches to loosen & tighten the threads. I tried to find a photo, and this one from Amazon was the best one to show the threaded back side.
I removed mine and took it to a local rv store, who had to order the right style and color for me. I think it cost about $35CAD. A little teflon plumbing tape on the threads, butyl tape to seal the flange, and the new one was installed in a few minutes.
Hope that helps!