Connie:
If you are taking Disney
bus transportation directly from Animal Kingdom to
Fort Wilderness, I'd give yourself a good hour to an hour and 15 minutes for the trip. You'll need 30 minutes for the bus ride but I'd factor in an additional 15 to 20 minutes to wait on the bus at the park (although waits are usually less) and then 10 to 15 minutes to transfer buses once you arrive at Fort Wilderness. (The bus from Animal Kingdom will drop you off at the Outpost Bus Stop but you'll need to get off and transfer to a bus headed to the Settlement where
Trails End is located. There are three buses you can take: Orange, Purple and Yellow. I prefer the Orange line because it seems most direct to me.) The ride takes 8 to 10 minutes depending on stops and let's you off at the Settlement.
The outdoor movie typically begins around 7:40 p.m. in the fall and winter following
Chip 'n' Dale's Campfire Singalong at 7:00 p.m. (during Daylight Savings it moves to 8:40 after Chip 'n' Dale's Campfire Sing-a-long at 8 p.m.) The walk from Trail's End to the amphitheater is about 12 to 15 minutes, so I doubt you could eat and see the movie. I'd recommend moving your dinner reservation up or ordering from their take-out menu and enjoying a picnic while you watch the movie.
Wishing y'all a magical vacation!
Whitney