The DH and I found that the bus service to WL was pretty good. Downtown Disney and Typhoon Lagoon are about the same amount of time since they are pretty close together. Blizzard Beach will take longer since it's more over by Epcot.
I would say at least 30 minutes to DD & TL. I can tell you that we had to wait a bit for a bus to come back and pick us up at TL for quite a bit, so make sure you build in time there. 40 minutes would be a safe bet.