We are planning a biking trip for October, and the website I am using as my jumping off point is loire-a-velo.fr.
Locacycle, mentioned in his book, also has info online at http://www.cycling-loire.com/organise-stay/location-loire-velo/loca-cycle-bike-rentals-amboise. They also seem to sell wine… I haven't been able to find any online info on Cycles le Duc.
http://dbrabyn.photoshelter.com/gallery/-/G0000KuGbAXr0E0E/2 I found these photos to be very motivating to make this part of our trip.
Other than that, it's the basics from the book. Eight miles from Amboise to Chenonceaux. The first two miles are uphill. White and green signs to follow as you go past Clos-Luce. The whole loop (Amboise, Chenonceaux, Chaumont) is 37 miles.