Cassis

Cassis is beautiful! Yes, absolutely the calanques boat ride. If you Ike to swim, recommend booking one that offers swimming time. One of the highlights for me! I also enjoyed the petit train which stopped at one of the closer calanques for photo opp. Enjoy a stroll behind the port along the quaint streets and little squares. I recall they had a nice market on certain days too.

Restaurants from my 2019 trip:

La Vieille Auberge
14 Quai Jean Jacques Barthelemy
Pretty good sole meunière, and scallops and shrimp sauté with tomato; Terrace seating on the port.

La Chaudron
4 Rue Adolphe Thiers
Cozy outdoor seating, casual, plat du jour fish and ratatouille was tasty and reasonable.

Bar le Port - my daily stop for espresso at the counter before heading to the bakery around the corner for croissants.

We just returned from France we spent 2 nights in Cassis - cannot recommend. There is a reason it's mostly visited on day trips. We stayed in the port ... the restaurants for the most part were at best 2 stars. The Calanques... don't do more then like 3 they are all the same. I did win 150 euro at the casino though. But if you go don't forget your passport you cannot get in without it but it's super little. There really isn't too much to do there. If you are wine people and have a car highly recommend a visit to Bandol. GREAT fun.

I tend to agree with Donna; unless you are hikers and it is hiking season (i.e., NOT summer), Cassis, lovely as it is, is not a place where you need to spend more than 2 nights, in my opinion.
Of course, if you want to relax by the sea, then yes, it is a good place to do so.
But the calanques' lack of water makes it hard to spend a leisurely day at, say, En Vau or Port Pin: you have to carry all of your water. So if you want hassle-free beach time, you are left with the beaches in Cassis itself, which are pretty, but small.

A couple of caveats. We allowed ourselves 2 days just in case of bad weather. Sure enough, it rained the 1st day. 2nd day dawned bright and sunny. However, the wind caused all the boats to stay in port. Perhaps with more days you will have better luck.
We decided to take a ride on one of those tourist trains, which promised to allow us to see the calanque from above. What a waste of money and time! First of all, we were told that the next departure was sold out. We came back, only to be told that the next departure had been pre-empted by a large group. When we finally secured places, the squeeze on the seats was really uncomfortable, and we are small people. The English narration was recorded and got out of sync with the course of the vehicle. I can’t imagine what could have happened to make the experience worse other than a serious accident.

We just finished a fabulous 13 day RS tour in Italy. We thought Cassis would be a good place to relax. We are currently, as I am leaving this message, at the Hotel de la place Mahogany in Cassis. We decided on this hotel for a 40th Anniversary celebration after reading about it in the travel guide and checking it out online. The view from the deck, restaurant and bar are great. The website is very deceptive. The photos must be from 20 years ago as is the terribly sagging bed. There is black mold in the bathroom (I am highly allergic), there is no door on the bathroom and the bathroom walls are glass. Even after 40 years of marriage there are certain things we’d rather not share.
Although most travel guide picks are winners this is one hotel to avoid.

Where was this hotel recommended?
Google reviews seem to agree with you, and I stayed there for a night in 2018 or so and was not impressed - work paid, but I remember a nondescript room at a rate that definitely exceeded my allowance. At least I hope you're having a good time in Cassis!
By the way, for reviews like this, don't hesitate to create a thread in the "France reviews" forum next time. It does not matter much, since your comment is Cassis-related, but it helps make threads easier to follow.

Thank you Balso for your response to my post. Silly spell check created a slight error in the hotel name, it is Hotel de la Plage Mahogany. We got the name of this place from RS France book. We think Rick Steves is amazing. I suspect that some things have changed since Covid prevented Rick & company from traveling to check on places and reviewing must be a long process.
Good point to check Google reviews, we were a bit harried making plans this time. We’ll make time for that next time. Certainly would have been worth it in this case.
We slept okay and today we will ask to have the mold treated. It helps that my husband is bilingual and my French is marginal. Communication will be easier and a photo of the mold will help. Although there is nothing we can do about the total lack of privacy in the bathroom.
Thanks also for your input about posting under reviews for France. I have never posted before and certainly posting there would be better than posting on a thread about Cassis restaurants. I had no idea where to post this. Thanks for taking the time to reply. I appreciate your help.