The same bus route serves Typhoon Lagoon and Downtown Disney. I believe that at least one resort has its DD bus go to Typhoon Lagoon first in the afternoon and at least one resort has its DD bus go to Typhoon Lagoon last in the morning.
Not sure about Blizzard Beach, maybe you have to transfer at a resort (Coronado Springs or Caribbean Beach or Pop Century probably the best bets).
Disney hints:
http://members.aol.com/ajaynejr/disney.htm