not sure if this place be to your liking, after yishun dam area there, got a new road leading to punggol marina (not fully connected)
from yishun dam going towards to the seletar airport there is a new road that cross over onto the 2 island behing seletar airport and all the way to punggol area (can see the new dam at punggol and the marina but road is not connected thru at the end of the road)
the road is wide 2-3 lanes in each direction. grass and trees with wide long straight road with almost no traffic and traffic light.