I'm not familiar with the "E" concourse - just A / B / C / D, which are all AA but D is also the international concourse handling some other carriers.

There is a SkyTrain which circles the airport and all of the terminals inside the secure zone. It's a couple levels above the departure floor, but there is good signage as well as escelators and lifts (elevators) to get you up to the station.

Not sure this is the best forum for the question (mods ?) - but I hope this helps.