Is the petting zoo gone? We were there in Feb and it was there in Big Thunder Ranch. It just had limited hours.
Anyway, yes, I vote for anywhere in NOS or Main Street for people watching. For a quieter time, the lower deck of Hungry Bear is GREAT! We just discovered this area on our last trip. There are bathrooms there too, so you can stay awhile. That whole back corner of the park after Splash is nicely (as in not very) populated during off-peak times.
Riverbelle Terrace, NOS, Main Street by the train station and castle.
DCA??? I would have to say by the wharf, but not anywhere near as much as anywhere in DL.
Anywhere in the hub on a park bench, just people watching or on the wall near the rafts to Pirates Lair facing the tavern, watching the pirate show and pirates on the raft.
In DCA:
Disney Animation
Near Soarin to listen to the music loop
To contribute, Animation Building for the win! Sometimes I'll travel from DL to DCA just to chill out when I get tired. (Kinda redundant, I know) I never get tired of the clips and with the comfy couches and AC, it's unbeatable for me.
At DL? Not too many spaces for quite time, but for people watching, Main Street for me.
Riverbell Terrace, when it is closed. This will be our 2nd trip that the Riverbell Terrace has been closed when we are there. My duaghter took a nap in her stroller and we sat and rested our feet each of the 4 days we were there. We people watched and played some cards. Very relaxing break.
Also on a bench between Main Street and the Castle. I'm always the one who sits and waits for the parade while DH takes DD on a couple of rides. I get a bag of popcorn or pretzel and a soda and just watch people. It's great!
We love to sit at the Carnation cafe and eat a snack while people watching! We also like the Riverbelle (?) restaurant on their terrace. Thanks for sharing all the other options with us!
During the daylight hours, anywhere in Frontierland or on the banks of ROA...
After dark...especially when the park is closing, I like to sit in the hub area so I can see the Castle and Tomorrowland all lit up as people filter out of the park.
We really LOVED Tom Sawyer Island!!
We spent probably well over two hours there checking everything out. Loved the pirate band and of course the special time with Captain Jack.
There was almost nobody there when we visited it, which made it even more wonderful. So many little nooks and crannies to explore!