Last time, I went to Bukit Perahu, which is in Tamparuli. It was a 30 min climb (by foot of course) and could be quite dangerously slippery when it's raining.
I have to say that I am quite fortunate to witness such a beautiful glorious morning view from the top of the hill. You can see the small town of Tamparuli and Tuaran from the hill and also the vast South China Sea from afar. You can go there in the morning or in the evening to view the sunset when the weather is fine.