Provence Itinerary for 5-6 days

To see the Mediterranean from Avignon, drive or take the train south past Montpellier to the long sandy beaches that stretch south to Spain. Frontignan, Sete and Agde are old beach towns (Agde is not right on the shore, however.) It's authentic Mediterranean but with a different feel from the small, rock-edged coves of the Riviera. Or, a little further east, the old Roman town of Arles, with its van Gogh connections, is just above the sprawling salt flats of the Camargue, a big nature preserve.

I should have added that we would like to go to St Tropez area if only for a few hours because of a WWII connection. So, should we have another home base to see St Tropez, and villages in the luberon region like Gordes? If so, any suggestions for a small family run b&b or hotel in the luberon region that would make sense for us to stay if we stay in Vaison la Romaine for 3 nights?

You are talking about a vast area divided by mountains. Consequently, as you suspect, there is no one base from which you could reasonably hope to see the Rhone valley attractions and St. Tropez as day trips. About 3 hours each way, Rhone to St. T.

If St T is a priority, I would consider reordering your whole itinerary Interlaken > Paris > Avignon > Nice and fly home from Nice.

I do not know if you are locked into anything yet, but your proposed itinerary entails 15 hours of train travel; the alternative entails 11.

We are flying out of Paris. We re-thought this and will stay the arrival night in Avignon, pick car up Tuesday morning and tour the Pont du gard and Nimes (forgetting Millau) on Tuesday, making our way to Gigondas for Tues night,or maybe a little further east village (not sure which one) and tour that area Wed, thurs and Friday. We will then make our way to the Mediterranean on Saturday to "see" it and stay overnight maybe in Cassis saturday. We thought we could explore the coastline before leaving for Avignon early afternoon on Sunday. Does that sound feasible? Thank you for your thoughts.

The seabourne invasion of the Riviera does not receive much notice from the general public, overshadowed by Normandy. The U.S. memorial and cemetery for this campaign is in Draguignan, less than an hour's drive inland from the beaches along the Mediterranean. It is known as the Rhone memorial, since the campaign swept up the river valley north to meet the western force at Lyon.
The site is small, dignified, and opened my eyes to a part of the hisstory I did not know. The cemeteries commission website has details here http://www.abmc.gov/cemeteries/cemeteries/rh.php

As an aside, the weekend I was there, the French artillery school just outside Drag. was holding its annual open house. Part of the event was a helicopter display by a joint French-German team, right beside the military museum dedicated to the wars the two countries fought against each other.

Thank you so much for this information. We know there is so much to see and do. Other than basing our visit on our interests and from the kind replies by people that want to help, we will try to get an itinerary together that will be sensible. Thank you all again for your input.

Following up on WWII sites, there is a very good Resistance Museum in Fontaine-de-Vaucluse that focuses on the Vichy regime, the occupation, and the resistance in Provence.

Stay away from museums of torture and other tourist traps however.

Fontaine-de-Vaucluse is also a dramatic site as the Sorgue river fairly bursts fort from the earth there and races through the town.