It's because of Liz and Marie we see all the nice thai people who're willing to help Americans in troubles... I wonder how many minutes they're behind Jeremy and Sandy.
Do you mean how many hours behind? They started at the Bangkok Bus terminal with Laurence/Zac, who finished ahead of Jeremy/Sandy. However, Liz/Marie had severe money troubles, so they must have wasted a lot of time walking.
I don't know precisely how far it was from the Southern Bus Terminal (in Thornburi) to the Bangkok Noi Canal (also in Thornburi). What I do remember is visiting that canal (known to the Thai as a Klong) and watching the floating feast come by of every conceivable type of food prepared on boats and offered for sale from those.
The Royal Barge Museum is also on the banks of Klong Bangkok Noi. I wanted to attach a map of the Thornburi district which shows the Klong and that museum, but it was slightly too large for RFF guidelines. If you want to see it, go to http://wikitravel.org/en/Bangkok/Thonburi
and it is on what would be the bottom right of the first page if there were pages. It is unknown where the "feed the fishes" task was along the banks of the Klong.
Just remember that World Race Productions or CBS editors are sneaky and want you to think it's a tight finish when it really isn't.