If you are spending time in the department of Dordogne, it is possible with the right planning to see 3-to-5 locations of this WH site in one day. 

My day in May of 2018 started with a wash. Grotte de Font de Gaume is among the most popular of the caves. You cannot buy tickets in advance, and only 50 people are allowed in during the course of the day. The caves open doors at 9:30am, and you realistically need to be there no later than 8:30 in order to get a ticket for some later time in the day. We arrived around 9:05 and were approximately at #70 in line, and left at 9:30 after hearing from the ticket clerk that our chances for the day were slim. I knew in advance that there was a fair possibility of that happening, but getting up much earlier to spend an hour or more in line for tickets is rarely an acceptable strategy for yours truly; I was hoping that in the shoulder season there may be less competition for tickets, but was proven wrong.

Instead, we went to Abri de Cap Blanc, where there was no line for the opening at 10am, and only a dozen of other visitors joined us in the following hour. This is not a cave, but a preserved rock overhang (abri means "shelter" in French), where the art form is not painting but sculptural relief. The sculptures were magnificent beyond any of my expectations. The small onsite museum has a few artifacts, exhibits, and replicas related to the primeval residents of the valley. Access to the actual sculptures is allowed only in small groups with a guide. The guided tour is in French only, but an English-language information sheet is available.

We next went to Grotte de Rouffignac, where it is possible to just walk in and get on the next tour of the cave. The electric tourist train goes almost two kilometers deep inside the cave, taking you to a series of monochrome drawings and engravings of various animals, dating from around 13,000 years ago. Interestingly, the guide stresses the fact that the cave was never really inhabited by the humans, and there is no good answer as to why people traveled so deep inside the dark passages to leave their artistic mark on the walls and the ceiling. The tour is in French only, but when enough English speakers are present the guide will occasionally switch to English. Companion electronic guides, with texts and pictures in various languages, can be rented at the ticket office for the duration of the tour.

Our final stop was Lascaux, the headline site of this World Heritage series, where a huge modern interpretive center (named "Lascaux IV") was built a few years ago to cater to the masses. Everyone who tours Vézère prehistoric sites comes to Lascaux; buying tickets online in advance is highly recommended, although I expect that in low season you can probably walk in without an advance purchase. English-speaking tours are scheduled only a couple of times a day, while French-speaking leave throughout the day every few minutes or so; I did not find the guide's commentary widely illuminating, but she did point out a few more obscure features of the paintings, so planning for the English tour may make sense for those who do not speak French.

There are no real caves at Lascaux IV (the original cave is located some distance away and has been closed to visitors for decades; a secondary cave - Lascaux II - can be visited with a French guided tour on very limited schedule). Your visit to the interpretive center will take you to the replica of the caves, and then your guide will deposit you at "the Studio", where you can explore the paintings and the history through many interactive exhibits. There are also a series of short movies related to the discovery of the caves and the interpretation of its art, as well as an exhibition of modern art inspired by the primeval paintings.

The reproductions of the Lascaux paintings - make no mistake, you are only seeing reproductions here - are polychrome, and almost too vivid to bring suspicion of not being authentic. But all available information suggests that the original paintings indeed remained in similar brilliant shape for millennia until their discovery in mid-20th century.

I used to think that primeval art was not exactly my cup of tea, but I am very much impressed with what I saw at the Vézère sites.

Majority of the sites are located no further than 30 minutes by car from either Sarlat or Perigueux. They are not managed by a single outfit and they all have different access policies, so advance research is paramount.