We took the Loire to the South of France tour this past summer. The tour was a lot of fun, with visits to more Chateaus than you can shake a stick at, spectacular Roman sites, cave paintings, and great food everywhere! What follows isn't a detailed trip summary but rather some musings, commentary, as well as a few things we wish we had known in advance.
The canoe trip seems to give rise to a number of concerns on the forum and on the tour people were a bit nervous before we went on the river, but there is nothing to worry about! The canoes are easy to paddle, didn't seem prone to tipping (nobody did in our group), and were dry. It was a pleasant paddle and very enjoyable watching the scenery go by. If you aren't careful you can splash water inside with the paddles, but nobody got wet enough to want/need to change any clothes. People were worried about taking cameras, but, again, no mishaps, and there is a waterproof barrel to put them in. I've heard you you are supposed to have shoes that stay on your feet and not loose flip-flops, but the canoe company didn't enforce the rule. Most people on our trip did bring a pair of water-type shoes; also useful in Nice if you go to the beach which is quite rocky. The one tricky part was when the canoe company guide had us beach the canoes since you need to beach and launch on your own. The one-person kayaks are a different story, they seem designed to let water in as part of a self-bailing feature.
The light show in Chartres was quite nice on the cathedral. It is about 10 minutes long and repeats for as long as you care to watch, so don't worry about missing it if you're not there for the start. There were other sights lit thru town, but the cathedral was the most impressive. It would be a good idea to practice taking nite photos with your camera so you know how to find the right settings.
In his books Rick encourages an independent travel spirit and taking ownership of your time and experiences. The tour gave life to this. There was a good mix of guided walks and free time on this tour. Several times we'd be given admission to an attraction (museum, castle, etc) and an orientation talk. Then it was "we've rented the audioguide for you, see it at your pace and then explore the town, get lunch, see you at the bus in 3 hours." Since the tour itinerary is in the catalog, spending some time at home before the trip with the guidebook and other resources (online, other guidebooks, etc) could be preferable to realizing "ok, we've finished the attraction, what now?" In other words, really plan for the independent part of the travel.