There is a Tomorrowland station that you get on to go to DTD and vice versa. It is not the "attraction" experience it is in WDW but makes a good way to get to DTD from DL.
There are two stops where you can get on or off. One is in Tomorrow land. Its near the Autopia cars and the Nemo sub ride. The other is in Downtown Disney, at the end near ESPN and the Disneyland hotel.
The ride itself takes you near the matterhorn, over Autopia, near Space Mt, thru part of DCA, and the GCH hotel