If it fits the budget, Gordes is where I recommend staying. L´Ile-sur-la-Sorgue is another great place to stay with an excellent selection of restaurants and the largest Saturday Market in the region. However, Cavaillon is perfectly fine and very central to the locations you will be traveling.
My go-to source for information about driving itineraries in this region is the Michelin Green Guide to the Luberon which proposes routes and recommended highlights. Make sure you include Uzès when you go to Pont du Guard and I find the Roman structures (la Maison Carrée, amphitheatre) of Nîmes to be more compelling than anything you´ll see in Marseille.
Plan ahead if you are going near Avignon in July as the festival attracts thousands and parking can be problematic.
If you have not driven much in France you should be warned about the thousands of speed cameras, some marked, most not. Tolerances are very tight so familiarize yourself with speed limits because they at not always posted.