The walk from All Star's/Coronado to Blizzard Beach is most definetly NOT 30-45 minutes! We did the walk and if you go at a decent pace, we made it from BB to All-Star Sports in about 10-15 minutes.
Walking to Typhoon Lagoon though doesn't seem to be allowed. When getting off the main road and past the entrance of TL, it is a winding road through the woods. I don't think there is a spot for people to walk, I may be wrong though.