You can stay @ Cherating Beach, 15 mins drive up north of Kuantan. Usually most travelers n backpackers will head to Kampung Cherating where there are quite a few backpackers' guesthouses. There is a quiet beach where you can relax or do a simple surfing as well.
There is a turtle sanctuary which u can visit, located approx 3-4kms north of Kampung Cherating (next to Club Med). It has a hatchery facility and you can release baby turtles at 7.30pm right after their video presentation.
Besides that, there is a fireflies tour by a popular private operator near Kampung Cherating. You need to do some googling on the net to find out more concerning the arrangement.
The border of Terengganu is just 10 mins drive up north and you might want to visit the laid-back Malay state for their renowned traditional boat making sites or the chance to chance upon local coconut collectors that use monkeys to do the climbing and plucking. :) about 8 years ago