If your children are into characters, Epcot is great for that. There is a character greet near Innoventions. That had Mickey, Minnie, Pluto, Goofy and Chip and Dale when we were there. When we went outside, Donald, Mary Poppins, Smee, Captain Hook and Baloo were there. We saw the Pooh characters in the English toy shop, and Belle and Aurora were in France, in the garden.
The time before last, there was a character bus that came to different locations at specific times. There was hardly anyone in line. It was much less crowded and more manageable than MK character greets.
As for rides, my youngest (4) loved Imagination and liked Spaceship Earth and the Mexico ride. She didn't like Soarin and HATED Test Track. DS (6) loved Soarin and said he liked TT but didn't want to go on it again.