http://www.holidaycity.com/cameronhighlandshotels/

This list is fairly decent. Equatorial, Lakehouse and Heritage hotel being quite established.

If possible, skip Cameron Highlands. It was once THE place to go but not anymore.

I would highly recommend Taman Negara Pahang (National Park) if you are into nature. It is fairly easy to get there from Kuala Lumpur (about 3 hour journey). 3 days trip would suffice unless you intend to trek deep into the tropical forest.