We have relatives in Kota Kinabula, Borneo and have used this as a base for a couple of holidays and there is loads to do.
They have all the posh island resorts as well as basic stuff. We used a rented apartment in the town as a base so saw the real town life.
We went on some trips up the mountain to the rain forest as well the tip of Borneo to the deserted beaches.
It is possible to easily hire and drive as well as have your own driver and guide. We have done both.
Would definitely suggest booking yourself.
From KK we drove across the island to the Orungutans stopping high in the mountain at the tea plantation as well as an isolated lodge.
Basically loads to do and lots to visit.
It can be basic at times depending on how much you pay and how much you haggle! We reckon it is not much more than 2 weeks in the med.
Last time we went via Singapore for a few days.
…finally you can also have guided mountain biking in the rain forest!!