It looks like you are staying at BLT. There is a small launch that runs from the Contemporary to Ft. Wilderness. It runs from 6:45 am till 11:30 pm (sharing with Wilderness Lodge). It drops you off at the Marina, so if you are doing something at the Settlement area, then no internal buses.
If you are trying to get to the campfire, it is a short walk from the marina (about 1/2 mile).
If you are trying to do the horseback riding, then a cab over to the Outpost might make sense.