Fantasmic has a dessert package, no dining package, and you get an actual seat for the show. Otherwise, as said, plop yourself down on the edge of the river and wait. You can leave one person with a blanket or something to save the spot so everyone doesn't miss out on that time. Grab a bread blow soup and people watch!
Alternately, for the best second show seating plan on being on the critter country side of RoA during the first show (go on HM, Splash, Winnie the Pooh, and you'll be in the best spot to get the best seating for the second show. They let these people in first, all other people are held in frontier land until CMs get the clear.