Is there a bus that runs from BB to TL and TL to BB during the summer season? If we wanted to do both waterparks in one day, what's our best plan for getting to each?
The buses for Blizzard Beach share with the Animal Kingdom and the Typhoon Lagoon buses share with Downtown Disney. So you will need to get on resort buses that go to both destinations.
Another option would be to take a taxi at a cost of about $11 plus tip and it would only take about 10-15 min assuming a cab is there when you are leaving one park for the other. Allow at least 60-90 min to make the trip via buses.