From T7 it's a quick 5-minute walk to Sepulveda. I have done it many times. Head east, not north. Pass the police station and carefully cross the 2 lanes of southbound traffic leaving the airport. Continue on the south side of the onramp from southbound Sepulveda to eastbound Century. Then walk north to the center of the lighted pylons. That's where you can catch a city bus or Uber southbound. Save time and save $4

This walking route has no traffic lights to slow you down, unless you need to cross Sepulveda at Century to catch an Uber northbound.