There is no direct bus to the parks from DTD. WDW realized a lot of folks were parking at DTD to avoid the parking fee. If you park at DTD you have to go to a resort and then take a park bus from that resort. Much easier to just pay the parking fee.
Not to mention the DTD buses to the resorts don't start until around 10 A.M. and that is from the resort. (They assume there is no one waiting for them at DTD since they have not delivered anyone there!) Figure an hour in the morning they just don't run as often so now it is 11 before you get near the park.