janet, I feel as though I did supply the key facts pertaining to my original question, which was regarding a guide for Ancient Nemea. I received very helpful feedback and was able to make a decision. The extra information regarding our group's age range was provided when tommyk5 made a suggestion for other, larger sites, so I responded in that context with additional background.
I will not need luck or patience to travel with these folks, and I don't need anyone to provide strategies to hold their attention. This is not our first trip together; it is not even our first trip to Europe together. The "kids" are fantastic -- curious, energetic, enthusiastic, appreciative. They do, in fact, read LOTS that is not on their iPhones (well, except for my special needs son who can't read at all, but that's a different story). They are extremely well-educated, smart, and probably know more than I do about classical history. They are just not going to delve into a guidebook, mostly because they are too busy with school and jobs, like my DNP grad student oldest who is also an RN working the hospital floors 30 hours a week. That is why I am coordinating the trip, not them, and they are thankful. As am I, because they are simply wonderful people and give me hope for the future.
I very much value and appreciate the information provided on this forum, and I have been able to plan this trip with very few additional questions because there is a wealth of background available if one takes the time to search (I do).
Thank you again to everyone for your very helpful information.
Deb