We loved the market in Riez, too - I think it was mid-week, but a really nice mix of pottery, food and vegetables, and 'interesting things'.! At the top of the hill overlooking the town there's a little nunnery with a chapel, and we had a picnic on the grassy area outside. The nuns were singing beautifully in the chapel, and it was a really magical day!
The Valensole plateau is fantastic in lavender season - you can actually smell the lavender in the air for miles around, and the lavender honey is just wonderful.
The Gorges du Verdon area is lovely - but busy in high season, so if you're driving around the Gorge then make an early start.