Hello there,
we went to Aix-en-Provence last summer for a week. Aix is a nice sized town, small enough to walk around but big enough that you won't be bored. One thing I will say is that a lot of cars, vans run through the incredibly small streets, so you would have to get used to jumping out of the way. A lot of people traffic too. That said, the town is lovely, typical french town. Lots of cafes, restaurants, quirky little shops. Some markets on every day or two. Plenty going on. I'd go back. There's a lovely hiking area too, if you want a day out of Aix. the town pays for a bus to take people there and back.
Restaurants tend to close between lunch and evening time, so if you're looking for a bite to eat, go at regular hours. Plenty of variety. I think it's worth a visit. Marseille is worth a look, a bus ride away and another lovely town with a Pope's place (plenty of history) is Avignon. Well worth a look. Bigger town than Aix. But Aix is much nicer as a base. Ask me anything else if you like.
mica