We will be staying in Antibes with some friends that live there in October and are planning to travel to Provence by train for an overnight stay. We are trying to decide whether we should go to Avignon, Arles or Aix. If you had to pick just one of these towns to explore a bit of Provence which would you choose?
For just 1 night I would pick Aix. It doesn't really have any "blockbuster sights", but the city center has beautiful architecture and a lovely atmosphere, with a big market on Tue, Thu, Sat (and smaller ones every day), lots of shops and cafés, etc.
Avignon isn't quite as charming IMO, and Arles is a bit harder to reach, which would eat into your limited time.
Absolutely second Aix. I find Avignon positively dreary, and while I really like Arles, for me Aix wins hands down for sheer charm and beauty. It’s got markets, great restaurants, the Cours Mirabeau, and loads of tiny streets to wander in. The medieval part on the north side of the Cours and the more rectilinear, 17th-century quarter south of it are rich in beautiful architecture.
If you’re very interested in Roman ruins, you probably should pick Arles. But if you just want an architecturally homogeneous town of golden stone with a relaxed vibe and peerless strolling, I’d pick Aix.
I too would choose Arles or Aix over Avignon. Arles has more sights to see than Aix if you prefer more specific sight seeing. In addition to things already mentioned for Aix, Aix also has the Cezanne house and studio walking distance from town. Given that you have only one night and that days are already getting shorter in October, I might choose the option with the option with the shortest travel time which is probably Aix, although I liked Arles best.