In Epcot, like others, we make as late a dining reservation as possible, and walk through a nearly totally empty World Showcase. Absolutely perfect way to end a day, or even a trip. That's how we've ended our last two trips. 2 trips ago, it was our last night and we packed our car and driven to Epcot on for getaway night. When we finally exited the park at about 10:30 after a 9:00 Teppen Edo reservation, our car was one of only 2 left in the entire guest parking lot.
At MK, we either hit Casey's 5-10 before closing or jump on a ride at 1 minute before the line is shut down. Buzz, Pirates, and Big Thunder are the ones we ride most at the end of the night.
About 2-3 years ago, we were fortunate enough to take advantage of a 2 a.m. EMH night at Magic Kingdom. I don't recall exactly how we killed the time after 2 a.m, but we leisurely made our way out of the park. When we finally got to the front of the park at about 2:40, we were literally the only people on Main Street. When we exited the park and started walking to the bus area, a cast member stopped us, asked us what resort we were going to, called on the radio to a bus that was waiting over to the side for stragglers coming out of the park, and verbally told the driver which resort to take us to. We were the only people on the bus. Having the bus to ourselves after a long day at the park may have been the greatest Disney experience ever.