There have been many good comments from other travellers and well worth reading. What follows is what I found to be important.
Day 1 Miri. There is a market that you can buy last minute things you may have forgotten or want before heading to Mulu and Camp 5.
Day 2 Mulu National Park. Climbing the Pinnacles isn't part of the Exodus trip for insurance reasons. If you want to undertake this let your group leader know as you will need to book a guide. Hiking is weather dependent. Large bags are left in secure storage and you carry only essentials.
Day 3 Camp 5. This is the only place you will need to bring your own sleeping sheet. Mosquito nets are provided everywhere else when needed except for here. They can be rented at the Camp for 10RM per night for a single. Twice that for a double. You will want one. The same goes for ear plugs. Towels are not provided. A book may come in handy. Hiking poles are not needed. Light travel umbrella came in handy and is often carried by the guides throughout the trip.
Leaches. These pests were only encountered on this portion of the trip and at the tea plantation. They seemed to have favorite people they attached to. Suggestions for avoidance include long sleeves and long pants and tucking pant legs into long thick socks (basically a leech sock). Stick to the middle of the trail and don't brush leaves with your body. Insect repellant and treating clothes with permethrin worked well.
Day 6 Kota Kinabalu Largest city you will visit and have the time to shop. This is really the only place to buy gifts outside of the airport. Also a good place to vary your diet.
Day 10 Tea plantation. The acclimation walk will expose you to leeches again. Hiking poles could come in handy if it has been raining.
Day 11 Stage 1 of climbing Mt Kinabalu. Poles can be rented from the guide for 10 RM per pole for the 2 days. Leave extra gear at park headquarters and only carry what you absolutely need. You will hike in groups depending on the number of guides and your pace. Accommodations at Laban Rata Resthouse include a bunkroom that sleeps 12--prepare accordingly. Nice beds and bedding--extra heat provided by your group.
Day 12 Summit. Wake up call at 2 a.m. and groups depart after light breakfast depending on their hiking speed. Extra gear is left in room. Take only the barest minimums. Hiking poles your option. Other hikers and guides and porters all are on the trail at the same time and it will be slow. Group will travel all day at different pace before finally joining up for good at park headquarters.
Day 13 Kota Kinabalu beach hotel. Nice pool and hotel offers massages. Hotel is far from town--65 RMs for taxi one way or shuttle bus with set times 20 RMs each way.