The boats do not go to the TTC from Fort Wilderness, one group of boats go to the Magic Kingdom (on your left walking down the dock), and the other group of boats go to the Contemporary and the Wilderness Lodge (on your right walking down the dock).
If you want to be there for rope drop, it depends on when you are going and if that's a busy time or not. If you want to be extra sure, I would leave by 8:15, although on REALLY busy times you might want to leave a bit earlier, and on slower times you can probably get away if you leave at 8:30.
On average it takes about 20-25 minutes I would say total once you get to the docks to get to the MK (once again depending on how busy it is).
As for the busses, I would give yourself probably around 15 minutes, normally that should be alright for that early in the morning.
