Well, JD swims in the pacific during his triathlon and Kim takes a job in Tacoma, Washington, so it's unlikely to be in washington so i'd say somewhere in Californa, also, the time it took for them to get to Tacoma in My Road To Nowhere would be about that distance, so i've narrowed it down to one state, but i can't say an exact city.

I have no idea. I have always wandered that. They seem t live near Las Vegas so i'm think Sacramento

The cast and crew call it San DiFrangeles. So basically a mix between San Diego, San Francisco, and LA.

Somewhere near Las Vegas. It didn't take Turk long to get there to pick up JD from jail

Somewhere in California because in one episode they showed a California area zip code and because of the other hints