Thanks to all for the help. Turns out that another option opened up after I posted this LAX query--upgrading LHR-ORD-SFO on 767s all the way, with lots of connection time in ORD--so I opted for that. Good to have this LAX info nevertheless for future use, including finding out about the fun bus ride.

(Now watch...there will be a huge snowstorm in ORD late next month as I'm supposed to pass through. Will serve me right.)