From watching the finale, Kawela bay is my best estimate for the location of the Jetskis. I say this cause you see Art/JJ's Helo go past Waimea bay, a quick view of Sunset Beach Neighborhood Park and then past the shot from the Ep 1 Preview thread pic 18. Kawela Bay Beach Park looks like the location the Helo's landed and where Hanopu St hits Kamehameha Highway looks like the scene where R/D get into their Taxi.
I also looked up a site to figure time of day from shadows, and if my calculations are correct, chateau had the correct shadow length, but calculated before zenith instead of after for B/R at Sand Island in the promo vid. I estimate B/R were at Sand Island walking to the helicopters between 1330 and 1345. The taxi to Aloha Stadium would have been about 25 minutes (9.3 miles) each way(depending on traffic), so looks like they lost close to an hour from this.
It looks like D/R's taxi took them to Tropical Farms instead of Coral Kingdom, which are ~1/2 mile apart and would explain how they found the paddleboards instead of the R/B.
Fewer places than I expected in the final leg, but one heck of a finish. I give WRP props for the edit, up until the Sand Island RB mistake, it looked like we'd have D/R turned away with B/R winning, or a B/R turned away with D/R winning. Then it looked like A/J might win after D/R were turned back, but that ending I never expected, especially after seeing they had to paddle across the pond.
Here's a picture of the route D/R took in getting to the finish mat twice: Red square is where I think Taxi dropped them off, yellow square is the mat, blue square is the RB, and of course the red line is their path.