You won't be left stranded. I've had a 5:30pm ADR at RFC, when the park closed at 5:00pm. There was a very long line in there and I got seated well after my ADR time. I was a little worried about getting back to my resort. However, when I came out there was a CM there with a clip board and a radio asking where everyone was going. Even that late there were two buses waiting for us. I was sent to the second one, along with a few other folks. The driver announced that he would be making multiple stops, but that he would get us back to our respective resorts eventually and that Disney never leaves anyone stranded and would keep buses running as long as there was anyone in any of their parks or restaurants. We did have to wait awhile for that bus to leave AK though, as he was waitng for more guests. It was probably about 2/3's full when we finally left. I remember there were still several empty seats.