Hello to all. I am in the planning stages of a vacation trip to Turkey. Of course, there will be time spent in Istanbul. However, I’m reaching out to learn about other destinations worth exploring, including day trips from Istanbul. I am planning my solo trip for late October 2026. I anticipate at least 8 days on the ground in Turkey. Note: I am 74 years of age, and an energetic 74. I enjoy walking and exploring. Also, some websites suggest Cappadocia, but it doesn’t interest me. I like architecture, historical sites, churches or places of worship, and, of course, food ventures. Thank you for any feedback and your kind attention to my request.

With only 8 days on the ground, youl will need to be selective!

Ephesus comes to mind as an obvious choice given your interests, but there are lots of other options. If you haven't already consulted it, the Moon Guide is excellent. And you might find some useful information in my old trip report:
Some Observations on a Fantastic Journey through Western Turkey

As you have not much ime, you may fly to Izmir and visit Ephesos (train station Selcuk), Aphrodisias (train station Nazilli), Pamukkale/Hierpolis (train station Denizli), all by train from Izmir airport and then fly back from Denizli DNZ to Istanbul.)