The TTC is a hub for the monorail system. All three monorail lines have a stop at the TTC and it serves as the transfer point for them.
It's not so much a hub for the buses, except (I think) for the buses that go from other parks to MK (and vice versa).
The only resorts you can get to directly from the TTC are those on the resort monorail loop (Poly, GF and Contemporary). For other resorts, you generally have to go to a park and catch whatever transportation exists to nearby resorts (can be buses or boats elsewhere).
The only boat that goes to the TTC (that I know of) is the large ferry that goes to MK and back.