We are also arriving on Aug. 14. Coming up fast now!
As long as you do a combination of early arrivals and Fast Passes you will be fine. We avoid MK and AK Early Mornings but we do go to Epcot and the Studios for the extra hour. Once the park starts getting crowded we head out and back to the hotel for a break. Then we hit another park later in the day. Just go with the flow and don't be concerned about the crowds (or the weather). Can't do anything about them anyway.
Also, take advantage of E-nights if there are any scheduled when you are there.