Thanks for all the complements...and yes I know these forums will cost me money lol. I started out here when I had a Sportster, then a Street Bob and a Deluxe before the Road King. I've always been a member of a forum for the bikes and cars I've had. ...
Many of us have done a similar route - my route was nearly identical to yours except I had a Fatty. It's a long route, and a bit costly, but in the end you can appreciate the King for what it is - a truly spectacular bike with fantastic handling and comfort.
Sorry I can't answer your other questions, but I'm guessing some parts are used interchangeable.