Service 35 plies to Tanah Merah Ferry Terminal (TMFT) via
New Upper Changi Road/Upper Changi Road, loops there and goes back
to Bedok.
About 2h 30min in total not taking the waiting time into
consideration.
On Service 30 the full trip from Boon Lay to Bedok should take
about 2h.
On Service 35 to Tanah Merah (assuming that you're going to
TMFT) will be about 30 mins.
Better yet, if you want a faster alternative, take the MRT to
Tanah Merah and change to Service 35 (if you're going to TMFT).