Can you help set up visits to other islands after the tour?
Welcome to the forum!
The forum is just other travelers, not Rick Steves staff.
That said, no, you make your own plans outside of the tour.
jules m they don't currently offer travel consultation services https://www.ricksteves.com/travel-help/consulting
This service is currently unavailable. We hope to resume this service
someday. Please check back in 2025.
If you want a service that will make arrangements ffor you, for lodging & transport, without a fee, you might consider several Athens-based agencies that are accustomed to working online with tourists from N. American and Australian etc Two that have longtime experience in this are Fantasy Travel & Dolphin Hellas. You email them with your dates (exact, not vague) and your preferred price range (in Euros) for accommodations, and they provide an itinerary for you to approve.
Be aware, however, that to get best results, you have to do at least a smidge of work on your own. If you give no indication of any preferred islands, based on a bit of research beyond Youtube videos, they may just provide a "cookie-cutter" version of the most popular destinations. These may be very crowded during your dates, or skewed toward shopping/nightlife that may not interest you. You should also be aware of island groupings that have convenient links during a limited. A few hours spent on a useful site like this - https://www.greektravel.com/greekislands/ - will equip you to ask for what YOU want, not just for what's the most "popular."
Your RS tour guide can give you advise on getting to the ferry port or airport after your tour. You can purchase ferry passenger tickets at any local tourist agency the day before or the day of travel.