I just want to add that it is never a good idea to try to leave any park right at closing time. Walk around for a while. Shop or window shop or do anything for around 20 minutes.
On our last visit we watched the MK fireworks and then just sat on a bench right near the castle as the hoardes poured down Main Street to the exits. After about 20 minutes we took a slow walk to the exit and the bus stops were quiet. It doesn't matter if you use Disney transportation or drive, just don't try to get out right at the closing time and you will have no problems.