You'll be fine. Disney won't strand you. There will be buses until the last guest leaves the park. You won't be rushed through dinner so enjoy your dinner and when you leave, you'll be directed towards the park's exit. It's nice to walk through an almost deserted and quiet park. Once at the exit there will be buses or if you are extremely late the bus lines will be consolidated and more than one resort will be on a route or you'll be taken to DTD where the buses run until after midnight. Or you could always call a cab.