Hi,
here below a video to get all the platinum medals (and the runner ups) in the Region 2, if you need some tips. This region is much harder than the first one. The Run Up bonus of Stage 5 "Take a load off" is very lucky based. I found that one quiet difficult.
To get a platinum you must get the Run Up Bonus AND the three bonus items (Bronze, Silver and Gold). Don't expect getting a platinum medal witheout them.
All credits goes to DEATHWISH1988REF.
Happy hunting in the Danger Zone !