I believed you can walk to the Radisson Hotel at the corner of Century and Sepulveda, cross Sepulveda using the crosswalk, and get to Terminal 1.
If you prefer to take a bus, you can ride Metro Bus 117 (Fare US$1.25) at the corner of Century and La Cienega to get to the Transit Center at Lot C. From there, you can hop on the free shuttle.