This is a good opportunity to get some nice park running and hills in Singapore. Mount Faber Park itself offers about 3 km of roads and paths from end-to-end. From Henderson Rd., take Mount Faber Rd. (or some of the paths paralleling it) east through Mt. Faber Park. Then head west, through Telok Blangah Hill Park, which includes a ~1 km path above the canopy — very cool!
You can do the paths just in the park, or from the Alexandra Canal, take Henderson Rd. for 2 km, along the wide sidewalks. It’s a fairly steady hill into the park.