My daughter & I spent a few days in Provence this June & we had wanted to visit Gordes & Roussillon.
The only problem was that we didn't have a car & were relying solely on public transportation.
When planning our trip, I'd spent hours searching for ways to travel to these beautiful villages by bus.
The only bus I'd found was only available during, "Vacances scolaires" (school vacation), which meant that the bus would travel to
these destinations during the school's summer vacation (started July 6th, 2016) Since we were there in early June, we were out of luck.
Anyway, a recent post prompted me to do a bit of research & here is what I found...
Starting April 17, 2017 ( through September 30, 2017), there will be a bus that travels from Cavaillon to Gordes and Roussillon (with Apt as its final destination)
Here is the schedule for bus #17
So, one could conceivably travel to Cavaillon (via train or bus) take bus #17 to Roussillon (departing@10:20), spend a few hours exploring Roussillon, then catch the bus (@ 14:55) to Gordes, visit for 3 hours, then head back to Cavaillon (@ 18:40)
If traveling from Avignon, you can take bus #7 to/from Cavaillon, and to/from Avignon.
If you're interested in traveling to Ménerbes, Lacoste, Bonnieux, or Apt, you can take Bus #18 from Cavaillon.
I know that having a car is ideal, especially if you want to explore the countryside, but some of us prefer not to rent a car, for various reasons.
Wishing you all safe & happy travels!
Priscilla