The longest time it takes to transit from one gate to another on a mainline CO flight (within terminal C/E which is all one BIG terminal) is about ten minutes in my estimation. This would be for walking, train or a combo of the two. Add to that another 5-10 minutes if you have to transfer to term B and you need 20 minutes MINIMUM for the longest gate to gate connection. This doesn't account for deplaning time (up to 10 minutes normally) and GA's closing the departing flight (potentially 15 (?) mins before dep). Add that all up and, if everything is on time, worst case scenario you would need 45 minutes minimum from arrival time to departure time.