Like me using Google Maps app to drive very familiar commutes anyway (in case of traffic congestions and road closures), you should also look up UA app's airport maps anytime you're going beyond one terminal. I just looked at the app and asked for directions from *ABL to 83, and it came up with a calculation of 35 min, including a 0-min wait for the bus at T4 and a 5-min ride to T6.