I've not ever seen a posted list of times or routes the buses use when traveling between locations. Generally, the buses seem to run about every 15-minutes (give or take).
As the PP said, there are no buses from DTD to any of the parks (or vice-a-versa), but the buses do run from DTD to the resorts. However, the evening buses from DTD to the resorts tend to be crowded, so factor that into your planning.