Hi Hannah
I've spent a lot of time in Mulu so should be able to give you some advice.
Unless you are flying in and out to Mulu the same day you will end up in Miri. Best budget hotel is Appollo around ?15 for two sharing, in centre, just get taxi at airport, fixed rate (?4) and go. Difficult to book any cheap hotels in advance, just turn up and if you can't get in Appollo there are loads close by. Mega is best out of more expensive hotels and they have website etc. Miri is very good for picking up a few supplies, particularly snacks for underground and walking. V expensive and limited in the park. A good day out from Miri is to visit Niah caves which you can do on the bus or day hire of a taxi (bird nesting, Tom Harrison history etc) See travel guides for more details.
In Mulu best to stay at Park HQ. Book as early as possible as they get full. they have dorms, rooms, rainforest lodges to suit budget. Four is a good number, ask for a deal to include breakfast. Eat at the Mulu Cafe, good grub then go over river for beer in Sweetwater bar (beer not allowed to be sold in Park). Beer is ?1.50 per can in park as most flown up, Tiger beer best. Try local brew Tuak to get really pissed. AsK guides/staff in office for details of how to get to other bar that they use. Bit further away but bit cheaper. Take bottle of duty free up with you if you want to get really pissed. I guess being BEC this will be important;-)
Book adventure trips in advance with the Park. They will not guarantee you any but the most basic trip. The water levels must be stable for both Sarawak Chamber trip and Clearwater Connection, both well worth doing. They also have HR issues and it can be difficult to get a guide. Be patient but if you do get sorted insist on the full trip as nicely as possible. Sarawak chamber for example they always try to turn you round at about the entrance to the chamber. Best to bugger off in all directions so you can appreciate the scale of the thing. I have seen many frustrated western tourists getting angry because they can't do waht they wanted to do - you will always get more out of it by treating all locals with a huge amount of respect and being very friendly. If you can get her interested the keenest and probably best guide is Syria.
Deer, Clearwater, Wind cave are all showcaves that you can walk to although many go up to Clearwater on a boat. Clearwater and Wind are morning trips, Deer afternoon/evening. Go to Deer as often as you can as the bat flight varies a lot and sometimes they don't come out at all. You usually have time to go the day you arrive and the day before you leave.
You can go up to Camp 5 and do the challenging steep walk up to the Pinnicles. They control this a little like a Himalayan Climb with an early start and turn round times. If you are reasonably fit and used to walking up steep hills it's a blast and the pinnicles are fairly unique. Cheapest way at C5 is to cater for yourselves provided you stocked up in Miri. Rather than return the way you came you can continue along the Head Hunters Trail to the Mentawai Station at the northern end of the park. This is less used and you can arrange to stay the night here and be catered for by the ranger. Then you travel downriver in a long boat for two-three hours including a few small rapids etc. Then taxi/mini bus to Limbang and on to Sabah or back to Miri either flying or by road across Brunai (boring). You can get from C5 to Limbang in a long day, or you can break it up by staying at the ranger station or a longhouse down the river.
Other thing you can do which very few folk attempt is to climb Mount Mulu (about 8000ft) not as big a M Kinabaloo but a lot less touristy. I think its done over two or three nights. It is best arranged with a private local guide/operator. If you are interested ask the park to be put in touch with Veno or Paris or other similar locals.
In Sabah can recomend Gomantong Caves to see nesting in operation (go round back and up to top to their village), Orangutan Sanctuary, and wildlife safari's on Kinabatang river (elephants, lot's monkeys)
If you want more specific info you can get in touch with me. I am only using Littletitan to reply to your query, ask around for how to contact Tim Allen I'm sure you'll find some way. If not have a great time and send my regards to anyone out there you meet.
