My eldest dd is 14, but she is aspbergers/autistic, so a little different. I would NOT let her go for long periods of time without us, but we do let her stay in the mission control while we ride Mission Space, for example. We do utilize fast pass in those situations though, so not generally for a VERY long time, usually less than 30 minutes. My younger dd is 12 1/2, and I would be fine with her going on her own for a longer period/distance, as she is very responsible for herself and ALWAYS has her cell phone, LOL. And if they were together and absolutely committed to STAYING together, I would be okay with the two of them going off for a couple hours. However, my youngest generally doesn't WANT to go off on her own, and also doesn't like feeling like she is responsible for her older sister, so I doubt that this will come up for us anytime soon. They have gone to the movies together on their own (we dropped them off and picked them up), though, and that was fine, so I am sure they would handle it fine. I prefer to not have them off too far on their own as they both look young, my 12 year old looks possibly 13 or 14, but my 14 year old is generally mistaken for 9 or 10; would not want anyone to consider them targets.