Your transcontinental will most likely depart from T2, most transcons use the gates on the backside of T2 apx 25-29. If flying on a 737, the 73 gates are in the main building (original worldport) gates 1-3 Or 16-18 (usually 1-3). Airbus narrow bodies use a variety of gates but prob in one of those two locations because the far end of the terminal (gates 6-14) which is the most difficult to get to is used primarily for wide bodies. Arrivals in T4 are rare unless you are flying intl.

Regardless of the particulars, as everyone said, barring delays, on time arrival leaves you plenty of time to connect and even stop by Starbucks or play with that fancy little iPad ordering system in T2.