If you want to see Proboscis monkey, Labuk Bay Proboscis Monkey Sanctuary in Sandakan will always be the first choice as it is 400 acres of privately-owned land which has been set aside as a refuge for endangered proboscis monkeys.
Do you know that you can have another experience of seeing these long-nosed monkeys in Garama River, Beaufort, located about 130km from Kota Kinabalu? It only about 2 hour ride from Kota Kinabalu.
Just go to Wisma Sabah building in Kota Kinabalu (next to Wisma Merdeka Shopping Complex) and look for any travel agents who can give you the cheapest rate.
A day trip might cost you about RM200 per head, including food, transport and river cruise.
Besides having the opportunity to see the Proboscis Monkey, one may also get the chance to see variety of birds.
mo story here: http://barefootedladymariah.blogspot.com/2011/10/proboscis-river-cruise-to-garama-river.html
Beaufort has a very impressive looking mosque that seemed very new to me.
It´s build in a typical south east asian way and i had a little walk around it to have a look.
I did not enter it though.
Not that i was not allowed so, actually you are generally quite welcome as a foreign visitor there, but i generally prefer to leave places of worship to the worshippers no matter what religion it is as i think they are probaply happier without tourists snapping photos of them while they are praying.
Beaufort township is very small-if you have even 30 minutes to kill, go have a look at the market. There are plenty of fruits and vegetables and junk food for sale. The market itself is unspectacular, located in a normal 'square' building.