Hi Bluedaze,
You will be pleased to hear that late August may not be as busy as you imagine. Most of the schools in the US are back by then so many of the visitors are Brits. Now that does mean that the villas are busy but the theme parks are not at their peak. This applies particularly to the last week.
There is a route to Animal Kingdom which is quicker than following the Disney signs, and that is to cross the 192 into the centre lane (as soon as you have turned right out of Formosa) and then take the left turn at Sherboth Road. I don't think this route is any quicker if you are going to MGM MK or EPCOT. When I am going to those I just follow the Disney signs and turn right off the 192 into World drive.