So, I just looked it up, for pricing and ages.
The Segway is 16+, and (currently) $99pp. KTTK is $74pp and 16+.
I think the Behind the Seeds might be the easiest for us all to do, since it doesn't seem to have a minimum age and it's less than $20pp. There's another MK tour for $30 that's ages 12+, too (the Marceline to MK one).