The TTC is the transportation and ticket center. If you drive a car to the MK, you park in the parking lot there and then have to take the monorail or boat to the MK. You can also take the monorail to Epcot from there. If you are staying on site, the bus from your hotel to the MK will not stop at the TTC, it will take you right to the entrance of the MK, personnal cars can not get there.