3 days in Avignon in June

Do you plan to visit Pont du Gard?

Driving is easy enough, parking will be an issue
There are not a lot of safe places to just pull off to look at views

For driver cost check Daytrip.com

Your time in Avignon seems reasonable. The Palais is big, cold and sparsely furnished, but still worth seeing based on its unusual history. I think you can cover the remaining site you mentioned in a day. Based on our experience, if you plan on getting out of the car, I'd cut back on Day 2's itinerary. The villages aren't that far apart, but you can't drive around as quickly as you'd think in rural areas. And, if you want to go into any of the villages, you'd have to park on the outskirts and walk in. We visited all four, but we had more than a week. With the luxury of time, a full day (or nearly so) for each was just about right. If you can, try to match up your days with the days of the market in each village. It's a fun activity.

You might want to consider a small group tour.
I didn’t find Avignon to be very interesting, and as I was traveling solo, I went on an all day tour with Viator which was great. It was a small group of about 6 or 8 people, and our driver was very knowledgeable. We went to Gordes, Roussillon, and Pont du Gard, among other places. The other passengers were from all over the world and it was fun getting to know one another.

ChristineH, currently both my trips are to the east of Avignon so Pont du Gard is not on the cards this time.

Wanderlust58, total car travel time for both days is about 1h 30m according to google maps. So, I thought that I still get about 8-9 hours for stops, wandering into the villages, lunch, etc - about 2.5 hours per village. But will consider your advice and perhaps drop something else on day 2.

rachele: will check out tour groups that you mention. That is a good idea since I wont have to drive and tour guides do make a big difference to the experience.

Google maps is notoriously inaccurate. I find that doubling the time that they say it takes puts you in the ballpark. Maybe I'm a slow driver. You might try viamichelin.com or francethisway.com for a second opinion.

I use viamichelin.com usually. I do add time to their estimates because they don't seem to allow for gas/food/comfort stops.

Both day 2 and day 3 are very reasonable to me.

But for day 2, rather than hitting all the big name villages, I'd rather stay north of the main Luberon ridge and see some less visited villages as well. For example, I'd do Gordes - Joucas (takes 30 min to visit) - Roussillon - Lacoste (a bit manicured, lots of art galleries) - Oppède le Vieux (semi-abandoned).

Or go to Saignon after Roussillon, then drive back towards Bonnieux along D232 through lavender fields.

For day 3, I'm not sure you need to linger in Sault - great landscape but not a memorable town. I'd keep going NW from Sault to visit Brantes (really, really lovely village IMO), perhaps stop by the bridge in Mollans sur Ouvèze (but you can skip visiting the village), and back to Avignon via the expressway from Carpentras.