@Tocaard, I’m sorry to say that when I was in Collioure in June two years ago it was a crowded zoo, shoulder-to-shoulder people, all restaurants full, beachfront full, music blaring in the middle of the day. A friend, who regularly went to Collioure, rented a property for a week in June. She said never again. I no longer recommend it from June-September.
However, I agree about all the places to go from Arles, including the Camargue where visitors can visit a manade (horse and bull ranch). There are excursions with skill horse and bull demonstrations, lunch with local music included.
Not in Provence but across the river in Occitanie: Nîmes, Uzès, and the Pont du Gard have a lot to offer.