Getting to Dairy Farm is pretty simple.

From the city:

Head towards upper bukit timah, onto upper bukit timah road. When you see the Rail Mall, prepare to turn right into Dairy Farm road. Once on Dairy Farm road, take the first U-turn, and look out for a small road turning into MOE Adventure Centre (because the one you need to go into has no signage). If you are driving, park near Dairy Farm road at the MOE Adventure Centre  lane, then walk back about 10 metres to the unmarked lane with a gantry. Head in, and when you reach a fork, keep left. When you see the huge open field, you are there.

From BKE:

Exit at Dairy Farm road, and look out for MOE Adventure Centre. Then just continue the route from above.