We went on Sunday in October, right after they had reinstated ee, or Magical Mornings. We arrived at 11 am, after eating at 1900 Park Faire. The characters were out in full force on Main Street, and we spent a good portion of our time there! When we did wander back into the park, we found Adventureland to be almost deserted. We rode Pirates with no wait at all. I cannot answer for Frontierland, Fantasyland or Tomorrowland, though.
If you plan to take advantage of Magical Morning, do Fantasyland 1st, then go to Tomorrowland, then to Frontierland... in that way, you can get most of the most popular attractions completed, and take your time in the afternoon.
We also went back on a Thursday in the afternoon for the parade (also a Magical Morning). After the parade, we went to Fantasyland, and the lines weren't bad at all.
Take you chances, and if you find you are getting bogged down, then hop to another park!