There are campgrounds in UPLB at the Jamboree site (see
Mount Makiling - Wikipedia, the free encyclopedia - Points of Interest). I just don't know who you should contact and I'm sorry that I don't have enough time to search for the appropriate website for you.If you know someon who's affiliated with BSP (boy scout) or anyone from UPLB, maybe they can help you out. I hope I was able to help a bit.
Thanks. ------