We take the 20 minute (from T1) walk to the city bus center.

Take World Way/W. Century Blvd to Vicksburg,
Left on Vicksburg 2 blocks to 96th St.
Right on 96th to the LAX city bus center.
This is NOT a scenic walk, but it's the best walk and it avoids walking along very busy Sepulveda Blvd ( thus avoiding Google map's #2 walking route and Google maps stupid #1 suggested walk -- see below).

Do NOT take the "Skyway" route shown on Google maps.
It requires pulling your luggage uphill on the overpass above Sepulveda Blvd.
It also requires a stupidly dangerous crossing, including taking luggage up and down curbs, at 96th Street.