For future readers searching this thread, I want to share my experiences now that I'm back from my trip.
Usually I take my own bike to Europe and handle the trip planning... this time I wanted a local source to provide bikes for my wife and I, along with routing, reservations, and luggage transfer. We did not want to travel with a group, which eliminated quite a few options (and saved a pile of money).
We ended up using "Detours de Loire" and were very happy with the results.http://www.locationdevelos.com/en/index.php
They offer a variety of pre-planned routes. We went with the 7 day "Wonders of the Loire Valley" with an extra night tacked on at the start for arrival and settling in.
The route started in Blois and ended in Saumur. We arranged on our own to spend three nights in Saumur at the B&B Casanova (great place)http://casanovasaumur.fr/?page_id=19&lang=en_EN
Compared to simply following the Loire Cycle Path, this company provided a lot more variety, getting us off the river up into small villages that we might not have discovered. The hotel arrangements were fine and the luggage transfer was a treat.
I've bike toured a lot in the U.S., Germany, and the Netherlands. This was a great addition to the travel experiences... in particular the food really was spectacular. The people were extremely friendly... my German isn't bad but my French is extremely limited... but never a problem. A phrase book--- especially the menu section--- came in handy.
For travelling from the U.S. it was easy to fly into Paris and take the train down to Blois, and delightful to spend time in Paris after the bike tour. And as much as I love travelling with my own bike and kit, it was liberating to hand in the bikes and then box up our bike clothing to ship home, thereby lightening our load.