Given that both Brent/Caite and Michael/Louie were seen at the Singapore Flyer, could we presume that this is their very first destination of the race, and where they get their Detour clue? The Flyer is roughly equidistant between the two options: 2.4km from Bugis Village, and 2.6km from Hong Lim Park.
Getting a taxi from Ulu
Pandan would be a problem.
Sad that there isn't much of a chance to showcase the public transport, yet again! (They're paranoid about spoilers, aren't they? Not that it stopped all the information we got from leaking out!)
I believe there are three locations that remain unidentified, all taken from inside taxis. Good luck!