Don't stay near the airport, if you don't mind, stay in backpackers lodge in the city. Easier for you to travel.

You can also stay in Tune Hotels, a little further off city, but they have free shuttle bus to city daily from morning till 9pm. Otherwise if you want to go to the city earlier, you can take the mini bus, which is very frequent like every 20 minutes or less.

Water rafting, mountain climbing, snorkeling are must in KK.

Food, go to water front in the city, opposite Le Meridian Hotel, there are lots of ikan bakar and stuff, eat there because it's nice and the sauce is special...

I am in the midst of finishing my website, which will have my 10 day full itinerary for people to refer. Will announce later so that those who want to go Sabah can refer to it.

Same lar, no worries. I had my 10-day backpack there.

In order to climb the mountain, you need to secure the place in Laban Rata, a rest house in the middle of the mountain.

I am working sleepless nights to work on my website, then I can post my itinerary, then you just take and go because it comes with direction, transport and price guide. Sabar sabar ah, gonna be up and running in November. When are you going?

Mt. Kinabalu is in Kundasang. But go to KK bus station early like 7am, sit in an Toyota Unser (RM18), don't take the minibus, no air-cond, very hot. Then reach at the base camp at about 1000-1030am, then register and start climbing.

Tune Hotels is about 20 minutes from town. Make sure to catch the shuttle bus, otherwise you would have to fork out RM20 to go back. I kena once.

Each day, have one activity enough, or else you will be too tired to do too many things.

asked the Sabahan here 

islands - Pulau Manukan or Pulau Sapi or Pulau Mamutik (personally i prefer Pulau Sapi, u can get ferrying boat from sea port)

mont climbing - u need 3 days/2 night at least b'coz u need to climb early next morning. 2 hours trip to kundasang. ---> climd to laban rata ---> next morning (peak)

hotels - there are a lot of good budget hotels around KK town but the most convinient u could try capital hotel or Api2 hotel (walking distance to everywhere. tune hotel also not a bad choice but far)

food - plenty but here is my recommendations

1) beef noodle (local speciality) - LOI KEE, Luyang Foh San Yen)
2) seafood - HOI WONG SENG (besides Promanade Hotel)
3) fish head noodle - near Satelite town (karamunsing)
4) should try out Gaya Street u can find plenty of food there.
5) Rest. Melaka - near Sinsuran for authentic Nyonya food,

till then

cheers!!!

Try to go to the City Bus Station near Kg. Air or Padang Merdeka, there were some cars to be rented where you can roam around the whole Sabah.

If I am not mistaken, to rent a car requires RM XXX. 3-digits and above. =)