First, I just want to say that our host, Andie, was excellent. She said she had only been doing this for two seasons, but she was a pro - knowledgeable, friendly, and engaging.
The tour started with a pickup at our hotel which we found helpful, but is not mandatory. We found it worth the cost. The timing of the tour in mid-October was just about perfect. The boat wasn't completely crowded, so we had room to move, while still plenty of people to talk to and get to know. The weather was also warm enough (around 24C/75F) to enjoy the outer deck and get some sun and comfortably tour the towns, but not feel like we were melting in the heat.
The itinerary included a stop in the town of Skala on Agistri, a stop off the uninhabited islet of Metopi for swimming, and a stop in Aegina (town and island) for some tourism. We were offered some snacks (sandwich wraps) on the way to our first stop of Skala.
At this time of year, there just isn't much to do in Skala, so we just wandered a bit and went swimming at one of the nearby beaches. Do beware of the sea urchins! This was the least interesting part of the tour, although maybe it's better during the summer season when everything is open and more populated.
Swimming off Metopi was so much fun. It wasn't a hot/warm spring, but the water was crystal clear and the perfect temperature. Andie told us the water was about 6m (19-20ft) deep, but you could see the bottom easily. Some of us - myself included - jumped and dove off the upper level of our boat into the water. We were provided pool noodles for flotation, if needed. Really a fun time. This is when we also were provided a lunch of roasted chicken, two types of pasta, and two types of salad. There was also water, sodas, beer, and red/white wine. A great spread.
Our final stop was the town of Aegina on the island of the same name. This was a great stop. Andie offered to take us on a tour of town and about 10 of us took her up on it. The others went off on their own. We stopped in town to get some pistachio gelato and sampled some pistachio goods (brittle, cream spread, pesto, etc.), as the island is known for its pistachios. Everything was great. We then walked over to the temple of apollo archaeological site (4 EUR entrance fee) which was interesting and a nice walk. The town itself was still bustling and fairly large, unlike the small and quiet town of Skala.
On the way back to Piraeus, we were given a snack of sliced fruit which was nice. It was hot in Aegina, but being back on the boat outside was not at all hot with the wind.
Protips - bring sunscreen, definitely need it in the Mediterranean sun! We forgot our towels and it didn't really impact us, but that's another thing to bring. You won't have phone reception out on the water, but totally fine on both islands (I had a local eSIM on Wind).
Overall, I would absolutely do this again!