Hill repeats in training for hilly race course

I am training for Muskoka LC and Peterborough HIM which are hilly courses but I don’t really have a long ride that incorporates enough hills where I live.

I can do repeats of the escarpment hills in Hamilton, ON; I am thinking of doing 5-10 repeats of a 4km climb that rises approx 150m is there any advice out there on doing this or should I just keep up with my long rides.

The number of hills on these courses is making me question my training.