There is a sidewalk so if you really wanted to walk, you could relatively safely. However, you will have to cross the busy Buena Vista Drive to do it.
When you come out of the front entrance to Coronado Springs, you will have to cross the street (there's a light) and then go to the right. Blizzard Beach will be down there a ways. Also, you will have to walk across the entire parking lot and that's really not for the faint of heart. You will also have to dodge the Disney buses that will be turning into Blizzard Beach. And you would have to carry all your swim gear with you.
It would take you about a half hour to walk in each direction. Quite honestly, I wouldn't do it since the bus is much easier and safer.