Mersing is a small town on the east coast of Johor that is perhaps best known as the departure point for ferries to Tioman (which is in Pahang). It's a bit bigger than you might expect and is quite an expensive place aside from accommodation but is fine to spend the night. There is very little to see or do here, however if you are interest in exploring, Air Papan to the north offers quaint little Malay villages by the sea and some interesting landscape.
If you have a few hours to kill during the day, Mersing has a Chinese and a Hindu temple both worth a visit (both near the first roundabout by the bridge)
If you are going to be on Tioman for a prolonged period of time it is recommended you check your internet before leaving Mersing as the internet facilities there are sparse, unreliable, and expensive. There are a few internet cafes in town, all of them around RM2 per hour.
Its best to buy anything you may need for Tioman in Mersing as prices are a little inflated on the island.
There are numerous hotels and motels around the town of Mersing. Early reservation is recommended especially when your travel coincides with holidays in Singapore or Malaysia.
The smaller hotels are most suitable for budget conscious travelers and they are usually run by family. Prices range from RM20 per night for non-aircon rooms to RM50 for air-con.
These hotels are most suitable for business and family vacation travelers. Hotel quality ranges from about 1- to 3-stars standard.