Have you ever noticed that once you are in the park you don't see anything outside the park? No sky scrapers, tall buildings, even tree our of place even though you know they are out there? Well Disney is really good at making the park an immersive atmosphere. When you walk into the park you are "raising the curtain" and "stepping on stage", the outside world does not exist, you are now part of the show which is why employees are "Cast Members".
If you notice, when you are in the park you also won't hear noises / music, see incorrectly themed Cast Members, or even parts of the Land from another Land as they want to keep this magical. When you step in, look around. Most walkways are red as this stands out against a blue sky. As you walk up Main Street and head towards Adventureland you will see that the foliage and architecture starts to change gradually, even the ground changes colour to brown to signify dirt roads. In Tomorrowland the ground is grey, in Liberty Square it has brown rivers (this is to represent the poop that used to be poured onto the street from pots).
If you look up, you won't see any buildings popping up above the Disney horizon. That is because Disney plans around items that you would be able to see and either covers them or disguises them. For example, in DisneyWorld when you enter Epcot's World Show Case and look at the Morocco Pavilion (when this was built, the King of Morocco actually sent their own artisan's to decorate this area) there is one building that is in the skyline, this is actually the Hollywood Tower of Terror. The reason for the colour of the Tower is because it was painted and the shape was to fit in with the Morocco Pavilion because they know you could see the building from Epcot and didn't want it to spoil the magic!
When it comes to height, Disney likes to play with that as well. The Castle in the center of the park is actually not as large as they seem that is because the bricks on the bottom are larger than the ones at the top so your brain thinks that it is taller than it really is. This trick is used on the shops on Main street, they are really only 1.5 story buildings but the windows get smaller the higher up you go so you think they are a lot taller. They even make Main Street seem longer by slightly slanting the shops so then the Castle looks further away!
