We want to sign up for a full day PRIVATE tour of the Amalfi Coast (we'll be staying in Sorrento). Do we need to do this ahead of time, or can we wait until we get to Sorrento? We'd like to make sure we'll have good weather on the day of our tour. Is this a valid concern? We're traveling late September/early October.
What tour are you talking about?
You can also go on your own. There are buses going back and forth along the Amalfi coast from Sorrento to Amalfi.
http://www.sitasudtrasporti.it/public/tpl/campania/5070.pdf
And from Amalfi all the way down to Salerno:
http://www.sitasudtrasporti.it/public/tpl/campania/5120.pdf
And the bus costs very little:
http://www.unicocampania.it/?lang=en¢er=inside&colonna=turisti&action=costiera&banner=costiera
As far as the weather is concerned, if I could predict the future I'd be a rich man.
There is also a hop on/hop of bus service, new this year, from Sorrento to Amalfi. It is more expensive than the normal bus service but reports say it is more comfortable.
Thank you for your suggestions, but we are two couples, and would prefer a private tour. I've edited my original post to clarify.
As of April 2014, Mondo Tours is offering daily 9-hour van tours from Sorrento to the Amalfi Coast (Positano, Amalfi, Ravello, etc) and back to Sorrento, especially for individual Rick Steves people. The cost is €45 per person. You have a driver who does supposedly limited guiding, but on my tour the driver had a lot to say. The only catch is that they need 8 people to sign up to fill a van. I just checked Sept 30 as an example, and so far they have 8 people for one van, and 7 signed up toward a second van. I took this tour in mid-May when it was still very new, and it was good, although at that point I felt they made too long photo stops along the way plus a lengthy lunch stop (each person pays for lunch), which made for too short stops in the three main towns. Maybe that has changed over time. This is an affordable and beautiful trip and day, much better than wrestling with crowded buses or trying to drive and park yourself. This is written up on page 1006-7 of the 2014 RS Italy book, and you can go to mondoguide.it and click on Rick Steves Shared Tours for more information and the status of their different shared tours on different dates. You can also e-mail with questions.
PS -- just saw your PRIVATE note, this same company may offer private tours too.