As for rate, I got my rate either from Orbitz or Sidestep. I reserved though more than a month in advance; in fact my reservation was made in late August and we traveled December 4. I find that as soon as I know I am going, I reserve the cheapest and then I keep looking. If you find something better, you can reserve that and cancel your first reservation.
When we arrived I used the courtesy phone to find the location of the shuttle. When we got to the area the shuttle was already there. The only problem was that we waited in line at the desk for more than 20 minutes but it turned out that it was worth it.