Sicily

Assuming you are asking about Rick Steves Sicily tour, there is a section for that:
https://community.ricksteves.com/travel-forum/tours

A more specific question will get you a better answer.

Do you mean things to do in the free time? Compare the guidebook with whats on the itinerary and see what grabs your interest. The tour leader will have a lot of suggestions based on your interests.

I’ve been on 14 Rick tours, my last one being Sicily. Our days were pretty full and I would say it offered the least free time of any of my tours. But in Sicily that wasn’t a negative. You had enough time in Palermo and Siracusa to do some exploring on your own. Otherwise, the towns we visited were for a specific site or activity. The tour I was on as in November and at that time the route included Ragusa, Modica and Siscli. The current routing goes to Taormina so I can’t comment on that. Rick’s Sicily guidebook will be available on Amazon April 16th. Get it, determine what piques your interest and go from there.

The Best of Sicily was one of my top 3 tours. I’m sure you will enjoy it and finish it exhausted!

Go early for a few days and stay after for a few weeks :-)

Sometimes you can get ideas from the scrapbooks of past years.

From our visit there in March, where we stuck to the east side of Sicily, I would say- Spend several days in the Ortigia area of Siracusa. Eat a meal at one of the restaurants in the fish market (La Pescheria) of Catania.

Agrigento was one of those things that I am very happy I saw, but have no need to visit a second time. I can recommend staying at Villa La Lumia B&B, which had a nice view of the Valley of the Temples and a fun dinner with the other guests.

Ragusa. If more time, Noto, Modica and/or Scicli.

OP asked about being "on the 11 day Sicily tour" (i.e. RS tour) so not a lot of leeway on where to go, other than before or after the tour.