On a short trip like that, where you are hopping around, I think that transportation is really important.
I would be willing to bet a lot of money, that your total transportation time with the itinerary outlined above would be AT LEAST double staying at GF as opposed to BW. Probably triple, honestly.
MK - GF monorail, BW dedicated bus
EP - GF shared bus with other MK resorts or monorail around to TTC, get off and switch monorails and take monorail to Epcot, BW is 6 minute walk.
HS - GF shared bus again, BW is 12 min walk
AK - GF shared bus again, BW dedicated bus
The shared buses at Poly, GF, and Contemporary are a pain and add a lot of travel time.