Just as a point of reference, My two sisters and I (3 adult women) travel as a group of three frequently. We have found that we fit comfortably into one clamshell on the little mermaid ride, uncomfortably into one of the nemo clamshells, comfortably with room to spare in a pirate ship on Peter Pan, and somewhat uncomfortably into one doom buggy on the haunted mansion - but we squish together anyway. Big thunder, splash, RnR, Buzz, and TSM, someone goes it alone. If you do the barnstormer, someone will go alone too - those seats are tiny! Winnie the Pooh is nice too bc you can all ride in one honey pot, even if you're not in the same row.