Hammer has some great advice. I'm in the same boat. Very hard well water at my house. I usually just go to my parents and wash or go to the local coin-op. And then do all the Detailing at home.
In my experience, the well water only becomes an issue when it dries. It leaves nasty hard water...
A lot of questions, but I'll only address the one about compounds and polishes. You can mix and match if you want to, but I would recommend sticking to a system. I highly suggest trying out Meguiars M105 and M205. Very user friendly and you get great results. Many other compounds use...
Just want to introduce myself. My name is Paul and I'm just outside of Rochester Ny. I've been detailing my own stuff as a hobby for about 10 years or so. I've been lurking here for a while and finally decided to join. I tend to do more reading than replying. Anyways, just wanted to say "hi"