I was quite impressed with Trail's End when we were there in June. Good food at a reasonable price. In October, I can't imagine you having a problem getting a table any time you go....I would not think a wait will be significant. If it is, it is a peaceful and calm area where you can spend some relaxing time while waiting.
I believe the campfire schedule changes in either Sepember or October.....so by the time you are there, it will probably be a 7:00 start time. The movie will begin around 7:40....from what I know. I know you can walk there from Trail's End but if you do, you will want to give yourself at least 30 minutes as it is not real close. There are buses that will take you there but you will need to check out a map to be sure.
I believe the petting zoo in October will close by 5:00 at the latest....maybe even by 4:00.