Congratulations on your Road King. Is this your first Harley? There are quite a few people out here that have Road Kings. One of the best suggestions I've heard yet as far as getting to know your bike is buying one of those service manuals. It's on my list of extras for my 03 bike coming in September. Good luck and welcome.
Twice the engine (obviously). Considerably heavier. You can find out just about anything you want to know about the RK on the net. You will just have to wait to feel the thrill though. Heard there's some pretty decent riding through the Keys.
1. Motorcycle course - Amazed what you will learn - plus might help on insurance
2. New seat - Stock will wear you out and if riding passenger, they will be miserable. I'd go Mustang or Corbin. I have H-D Touring Seat and it's still not comfortable for passenger.
3. New handgrips - Need thicker ones to reduce some road buzz. Even though RK is SMOOTH, I experienced some.
4. Service manual - Hey, may not turn a wrench but it's better than the owner's manual. Never can tell when you may find someone who can do minor stuff without the $55 - $65/hour charge of most H-D dealers.
5. Extra lights - I put on Kuryakyn LED Brake & Turn Signals because I wanted people behind to see me when I was stopping, turning, etc. Next planned is front turn signals.
6. Go slow about making it pretty(i.e. chrome, etc.) - I started out thinking I had to have bunches of stuff. But after looking it over, I started going with function over looks. (See #4 above)