We have celebrated adult birthday's (mine and DH) at WDW w/ our DD's.
Had great times at California Grille at the CR. Book your PS around the MK fireworks.
The R&C in Epcot, make PS at 7:30PM and ask to sit on patio and view Illuminations.
If your into something rowdy, try the Whisper Canyon at the WL or the Hoop-dee-do Review at FW.
Let me know if you need detail info on any of these.