As it gets closer to my hike, it looks like I may be able to contribute more useful information for any potential rim to rimmers.
Today I called Trans-Canyon Shuttle to make my reservation for the 1:30 PM October 4 departure from the South Rim to the North Rim (arriving at 6:00 PM). (Incidentally, the shuttle leaves from exactly where I'll be staying the night before after my hike -- Bright Angel Lodge.)
I learned that they do not accept a credit card, only cash or a check. I was asked to send $ 45 via snail mail to confirm the reservation with the remaining $ 40 ($ 85 total fare) due at ride time. They will mail me a confirmation letter (and a confirmation # was given over the phone).
The gentleman I talked with was very friendly and accomodating -- I remembered his voice from a call last year getting VERY preliminary information!
BryanB -- appreciate the information about Phantom Ranch.
