Adult trips are a much slower pace for me. I took my nephew in November and it was go, go, go! He didn't want to sit for a minute. I like to people watch, there was none of that. Without kids, I like to sit and watch the Streetsmosphere performers at DHS. I also like to sit on the lower patio in front of the Plaza restaurant at MK and just soak up the atmosphere. I'll do FOTLK twice in a row, ride the People Mover round and round, spend more time in shops, watch all the performers in the countries in Epcot, things that kids never want to stop for. I love the Chair balancing guy in France. I also like to watch the kids meeting the characters. I sit on the bench across from Jasmine and Aladdin come out in Morroco or in the little garden in France where Aurora and Belle are and just enjoy seeing the kids meet them. I also love wandering around the resorts. I take the monorail and stop at each resort just to walk around and look for things I've never seen before.
ETA: If you like World Showcase. On my solo trip, I watched Illuminations in Germany and let most of the crowds leave after it was over, then I took the long way back going towards France, it was so nice, just a quiet, no crowd walk around WS.