If @OBNurseNH hasn’t already pointed you to this older topic she started, you can skim though it for lots of non-ride items that were being suggested: Off the Beaten Path - atypical experiences in each WDW park
Also, @ryan1 has a similar topic going: Off the beaten path...err...park
I noticed you haven’t been in WDW since 1999 and there have been an incredible number of changes since then. I’ll add some of my own items later tonight.