i would suggest to go sarba the highest mountain in asia i guess
kota kinabaru..... after you can go skin diving at one of the island, or go for a grade 3 white water rafting.
if u going for the Gunung Tahan, malaysia. 7 days. $450
dont think it enough unless u all start half way.
As Uphill jungle trekking & river crossing total there are around 7 hill or mountains. and to complete it from the starting pt to the ending pt will take more den 7days to do it. not every one can take it as it you u need to trek up and down and cross river etc. not once, not twice but more den that.