Hi,
The walk is about a half a mile.
Yes, you can walk from YC/BC to Boardwalk. Depending on your exact start and stop points figure about one-quarter to one-half mile.
Is it really a half mile? Wow. It doesn't seem that long.
a 1/4 mile going, and 3/4 mile coming home
YC is closest to Epcot, BC next, then on the other side BW.
It's not a bad walk at all.