Stay across the street from SWF at the Renaissance, go for club room if you can afford it. They usually have lower rates during the holdiays like July 4th.
After your DC visit, you get 7 days at SWF, and you'll want to take your time and visit.
You can drive over to Disney from the Renaissance going early each morning. Do Disney first with the large crowds. Then do DC which takes an entire day and you can relax. That night, you can visit SWF and pet the dolphins. Then go back the next day and do the penguin tour and continue doing the attractions at a laid back pace.