KK is quite boring, 1 night there is enough. Mount Kinabalu a great climb, just dont eat anything from Laban Rata, everyone gets foodpoisoned there. Dont go to P(B)oring Hotsprings, just a tourist trap. Sepilok is nice if you want to see Orang Utan. Then head for some trekking in Kinabatangan. End your trip with a week diving around Sipadan, base yourself in Mabul in for example
http://borneodivers.info/ .