Mark and Michael "have to get [their] backpacks" at Sathorn Pier, so that's probably where the Roadblock ends. Something to do with boats on the Chao Phraya? Michael has the fanny pack though. Come to think of it, if the Roadblock brings you so far away that you need a taxi to get back, wouldn't it be... common sense for the partners to bring the bags along?
Mark has his shoes in the preview, so Michael's likely to be the Roadblocker. With their taxi going north to Bang Rak (good eyes, Nam_Tuna!), that's the direction the Roadblock starts?
(Also: If the Roadblock starts along the river as well - eg Bang Po, I can see a return boat being faster than a taxi.)
Assuming seats are availabe on the second-to-last Guangzhou flight: if a team makes it on the Hong Kong connection the next day and the brothers are on the last Guangzhou flight, that would mean they're at least three and a half hours behind the lead teams this week?
Yoo bangpoe, gorjaglub bangpoe, koeyyoo bangpoe, gorjaglub bangpoe...