Yes, you can walk to Cape May from EPCOT. We have done both experiences. I will say my children found more to eat at the Cape May but my pick is Biergarten.
Here is why:
-live music, ambiance makes it for us the "Oktoberfest" feel
-German food is hard to find in our town vs. Cape May
-Buffet is well appointed at both but I believe Biergarten is cheaper...
-location, location, location...no leaving the park
-The chicken dance....period.
-B E E R
The food was good at Cape May but I would not say "fabulous" Certain items were very very good and others just so-so. Overall just average. Dessert nice. Wider variety at Cape May, however. I can't be bothered with crab legs...and DH who did bother with them said they weren't very good.