I'm not sure it's possible. The parade heads first from Africa to the main entry, but even if you stood by the bridge leading to the entry area, the parade won't be over until 4:20-4:25ish. It would be a close call getting out to your car and over to the HDDR in time, and unless the busses came just right, almost impossible on Disney transport. Sorry, I wish I had better news - especially since that's my favorite parade!!