From:

San Fernando Valley: take 101 south 
Glendale/Burbank: take 5 south 
Pasadena: take 110 south 
San Bernardino, San Gabriel Valley: take 10 west to101 north 
Orange County: take 5 north to 101 north 

Then, as you approach downtown Los Angeles: 

Take 110 south 
Exit Wilshire Boulevard; turn right onto Wilshire 
Go 4 blocks to Witmer Street; turn right onto Witmer 
Go 1 block to the Pacific Dining Car at the corner of 6^th and Witmer 
Turn left into parking area 

From Santa Monica:

Take 10 east 
Take 110 north 
Exit 3^rd Street West 
Go to the first signal, Beaudry, and turn left on Beaudry 
Go 3 blocks to 6^th Street; turn right onto 6^th
Go 4 blocks to Witmer Street; turn left onto Witmer 
Turn right into parking area