Opening scene errors

I just noticed this today...

During the opening scene, Lucy and Linus walk out of their house, down steps, and walk through leaves, past people's houses on their way to the pumpkin patch. They pick their pumpkin and head back toward their house, but not before coming to a fence that Lucy walks through and Linus has to walk around. Where was this fence before, when they were walking to the patch?

Linus loses control of the pumpkin and it starts rolling with him attached to it. He's doing all this on a sidewalk now. Where was the sidewalk before, when they left their house? Clearly the sidewalk leads up to their door, but wasn't there before, when they were walking through and kicking leaves. Also, the steps to their house were originally red, then upon their return home, they're white and then purple.