Just back from our vacation. Thanks again for the very useful help!

We ended up going both ways. I agree that going above-ground is a bit easier and quicker, but sorting out the tunnel was fine as well...though I'd still be at a loss as to how to describe this well without DeLee's help! But even if someone finds themselves at ORD without access to FT, ask around and you can find your way to the Hilton using either option.

I guess my basic advice would be to go outside if the weather is ok and you're traveling light enough to take your luggage across a couple of lanes. But if not, the tunnel is ok.

Some delays getting to ORD from SFO on UA due to first technical issues and then weather, but we made it with oodles of time to spare. No delays on the LH flight.