The closest part of Epcot, straight line distance from OKW, is Epcot's CM parking lot and CM's entrance.
For guests, there are only two entrances. Walking to the main entrance would be to walk along Epcot Drive, similar to walking along an interstate highway, but one without a breakdown lane. You'd be in the tall grass all the time.
The other way would be to walk to the International Gateway. Safest way there would be to first follow the path to DD, then walk along Buena Vista to the Boardwalk, then follow the boardwalk pathway to Epcot's entrance. Problem here is that Buena Vista is 3-lanes of 45mph traffic with no sidewalks. You would also have to cross the overpass over Epcot Drive. There's no sidewalk on the overpass.
Remember that eventhough many things are physically close together within Disney World, the place is designed to make everything feel far apart so that when you're in a park, you feel completely removed from the outside world.
Even the OKW pathway to DD is twice as long as the straight line distance would be if you could just walk through the golf course, trees, and parking lot.