Yes there is Wifi. The United Checkin usually open 3-4 hours before the departure. Due to the gate security, you will need to head to the gate a minimum half or more before departure. Depending on the gate number, you will either board through a jet bridge or sit and wait for a bus to take you to the plane (10-17 jet bridge, 12a, 12b, 17b, 31-36 bus). If you are mileplus premiere, enter the airport from the First Class entrance for convenience, and you can check in there.