We wondered about this question....but thinking about the upper end of the age range. We signed my mother and father-in-laws up for the tour...both in their mid 70’s.
We were told if they could stand for long periods of time they would enjoy the tour. Both were able bodied so we bought the tickets. Father-in-law had a great time and would Kiley do another Segway Tour. Mother-in-law had a slightly scary experience (not feeling in control of the Segway when disembarking) that made he feel a bit of tension throughout the tour. Although she was obviously cautious the remainder of the trip, and will probably never attempt such a tour again...she still had a good time and kept up with the group.
The beautiful part was my mother-in-law was able to go a long distance, see and hear everything we did, smile for photos at all the same spots...basically she got to do everything the group did,,,without walking. She would not have been able to keep up had we been walking. (Down deep inside, I think she thoroughly enjoyed the tour.)