I would save the money and stay at BWI. We love the Epcot resorts and with you planning on Epcot evenings, the entrance from the International Gateway is so much easier than the main entrance, and you can't beat walking back to your room at night. Plus, you'll be there during Flower and Garden Festival making staying near Epcot even more attractive. Plus, you will be very close to DHS and only a 10-15 minute drive to Animal Kingdom. Boardwalk doesn't often share busses, but GF does. If you were debating Contemporary vs BWI, that would be a tougher call to me. But GF doesn't have any walkable to park. We used the Minnie Vans and busses when going to MK last week from the Epcot resorts. It was super easy. We've had to wait on a resort monorail for just as long as a bus at times when staying at MK resorts. Plus, they are known to be down for service often, as well.