Aix or Marseille

Gordes and Saint-Remy are only about 45 minutes apart by car, and Aix is only about an hour from either. I would recommend staying in Saint-Remy for 5 nights, and Aix for 3, and visiting Gordes and other towns from S-R. Gordes is a beautiful place to visit for a half day, but not as good as S-R as a base for road trips in terms of driving in and out.

When my wife and I stayed in Aix last May, there were regular express buses every 10 to 20 minutes from the centre of Aix to Marseille’s Saint-Charles station, which took about 45 minutes. It was about a 15 minute walk from the station to the old port in Marseille, or a local bus ride. Aix is definitely a more charming base than Marseille, but Marseille is certainly worth a day exploring. (We very much enjoyed the “Old Marseille neighbourhood tour and treasure hunt” with Eric, that we booked through AirBnB Experiences.) As for “grittiness”, I guess we didn’t find that part of Marseille- it’s busy and old, but we never felt unsafe (we’re in our 70’s).

With your stated interests, I would definitely stay in Marseille, from where it is much easier to explore Cassis and the Calanques.

I actually think that the village of Cassis is skippable, though...small, very commercialized, no more remarkable than other coastal towns...the main draw is the Calanques, and you can visit them by boat from Marseille as well as by walks/hikes of varying difficulty also from Marseille. The easiest walk being the one from Luminy (end of bus B1) to the Belvedere de Sugiton: 1:15 round-trip on mostly level ground except at the viewpoint itself.

You don't say if you'll have a car or not. A friend who lived in Marseille had a 2-hour commute to get to her job in Aix once a week, using buses. On the other hand, it's a 20-30 minute drive if traffic is flowing.

We spent 6 months in Cassis many years ago. It is a beautiful setting and has the magnificent Cap Canaille in addition to the Calanques. But it's in a bowl, so traffic and parking can be difficult, awful. If you are driving, go early in the day. There are a few buses a day from Marseille and the train, but the train station is several kilometers above the town near the vineyards. When we were there, no sidewalks existed for the walk between the station and the town. You don't mention walking the Calanques, but the classic walk is from in town to the first Calanque, Port-Miou. The next one is the beauty you see in a lot of photos, Calanque d'En-vau, a bit tougher walk up and down. The walk is very rocky, some rocks slippery, worn down by so many hikers. I'd suggest poles. The trail continues on to Calanque de Sugiton but I've never walked out there. The boat ride takes you.

If you have a car, the drive to Marseille and the drive to Cassis take about the same amount of time. I'm fond of both towns but would choose Aix if I had a car. The airport is between Aix and Marseille.

Thank you all so much!! We will have a car. The debate continues....I am now looking at staying in St Remy for five nights as the first responder suggested. But do we need three nights in Aix/Marseille? Is there another place we should be doing an overnight in addition to two nights in Aix/Marseille? We have traveled in other European countries and I understand the difficulties in moving too much but maybe we need a night to start in Arles or somewhere near some of the more Western towns on our list. We do have a big list of places we want to explore or stop through that will obviously need to be narrowed down including the following...
-Arles
-Pont du Gard
-Uzes
-Nimes
-Les Baux
-Vaison-la-Romaine or Gigondas or somewhere in the Côtes du Rhone
-Gordes
-Roussillon
-Bonnieux
-Aix en Provence
-Marseille
-Calanques
I am still in research mode to narrow down the places we will go. I am trying to secure lodging first and trying to determine with our interests, where it most makes sense to stay. Thanks again!!!

Nîmes, Pont du Gard, and Uzès can be visited in one day. All three are an hour to Avignon or Arles.