In all likelihood, you'll be given a 3-hour parking pass when you get to the guard shack at the WL (and yes, they do tow). They don't allow folks to park at a resort in order to visit a theme park, there wouldn't be any room in the lot for the WL guests if they did.
If you're coming from offsite and driving, you have a couple of options:
1. Go directly to the WL and have your breakfast, then move the car to the MK parking lot.
2. Go straight to the MK parking lot. You'll need to take the ferry or monorail to the MK, and then catch a boat to WL.
At that hour, you're better off just going straight to the WL, I think.