Dordogne

It sounds as though you and yours have a pretty good handle on things. So, suggestions about what?

Reservations are good but I would not sweat it. That time of year you will probably be fine just showing up 30 miuntes early.
There are many fine B&B's around both Beynac and Sarlat to choose from. We stayed at one in Montford.

Adam,
I'm trying to choose a base hotel, somewhere that will be central. I understand Sarlat can be a nightmare to get in and out of.

John, Thanks.
Which B&B did you stay in?

Have to say I didn't find Sarlat to be a nightmare to get in and out of at all. Hotel Montaigne at the south edge of the old center has parking in front. And big rooms.

We stayed in Beynace which was a wonderful little village; would suggest Sarlat for 4 nights as there are more choices for dining and a lot more shops. Our B&B was Le Petit Versailles-a wonderful place outside Beynac.

We stayed at Villa des Consuls in Sarlat. We did find street parking available. Just do not order breakfast at the hotel. Also, I would not recommend Rapier restaurant. Not that difficult getting in and out of town.

Nancy: Check out the Hostellerie Maleville in Beynac (just google it). We have stayed there and loved it. As an added plus the restaurant at the hotel is fantastic. Beynac is very charming and a good base for exploring the area. Have fun.

Well, as others have said, Beynac is great. I think that other small towns on the river would also be wonderful. Sarlat is charming an certainly worth a visit. For the caves, reservations ARE a good idea at Font du Gaume even in the off season. OTOH we had no problem getting into the breathtaking Peche Merle (on the Lot) without even calling ahead. So it probably varies. English language tours may be limited in the off season, but the caves are worth seeing in French anyway, so be flexible if you can.

sarlat is bigger with more options. beynac, the caves and other prehistorical sites are all within driving distance. You can day trip to multiple sites on the same day.

Another vote for Sarlat. Having been to both towns, Sarlat is quite charming at night (and flatter, if that matters to you) to walk around in. Market day in Sarlat is wonderful, and the restaurants had great food. Parking didn't seem too bad, and should not be much of a problem in late October.

We stayed five nights at Le Petit Versailles in Beynac a couple of years ago and liked it, and the town, very much. The Fleurys speak some English but not a lot, they are very considerate and conscientious innkeepers, the breakfasts are great, and the setting, on a hillside overlooking the valley and several castles in view, is hard to beat. It's about a ten-minute walk from "downtown" Beynac on a hillside. Beynac is basically one intersection, between a steep hill and the river, with I think three restaurants, all of which we liked. There's a small hotel it the intersection too. Good jumpoff place for Lascaux, Font de Gaume, Les Eyzies, Castelnaud, Domme, and other sites, plus having its own hilltop castle.
Sarlat is much bigger, with a lot more choices for eating, sleeping, and shopping. Wonderful old medieval streets and buildings, an interesting walking tour, and street markets I think twice a week. The traffic there was very bad when we visited, but mostly due to construction that must have been completed by now. Apart from the construction, of course it takes longer to get in and out of a bigger town than a tiny one. We were happy staying in Beynac and visiting Sarlat twice in five days, but we're not that particular about dining and not much interested in shopping. I think your choice depends really on whether you want a more urban or rural setting. Either way, you'll love the Dordogne.

La Bard. Nice people, good location.

Thanks for all the great suggestions; they have been a tremendous help.