It is a nice walk to either park.
The tricky part is the walk to your room.

Check-in is in the middle of the two buildings, Inn and Villas. If you don't have a Boardwalk view, your room could be quite a hike from check-in. It could be very much closer to DHS than to Epcot.
Regardless, I am a born and bred NYC girl and I don't mind walking. Boardwalk is a fantastic resort; the Bakery is great for breakfast after a brisk walk/jog around Crescent Lake, and it's an easy stroll to either DHS or Epcot. Can't beat the location.
(so why then, WHY did I buy DVC at Old Key West?? Because I like life even more laid back.

)