***KLIA to Tioman Island

Get to Subang (the old airport) and then take a flight to Pulau Tioman?

Berjaya Air

Other than that is to take a bus or the KLIA Express the Kuala Lumpur city centre, and then take an express bus to the east coast.

From Sepang KLIA to the old airport of Subang does involve some costs.

You could fly to Tioman and road it back, or road it there and fly back.

Its a long way to go by road... the best option if you intend to travel by road is take the express bus from KL Sentral to Johore Bahru and another bus to Mersing where the ferry is.
If by air fly airasia.com KLIA to Johore Bahru and take the bus to Mersing. Mersing to Tioman by boat. Flying to Tioman is quite expensive unless if you get a package from Berjaya Resorts on Tioman ...
as Berjayaair belong to Berjaya resorts. Check out at berjayaresorts.com.

From KLIA get the bus or train to KL Sentral, then take bus or taxi to Pudu Raya bus sstation, and take a bus direct to Mersing. No point going via Johore Baru.

I flew 3 times with Berjaya already and it's really okay.

Better than their hotel @ Tioman which is more run down every year. Hope they will renovate it one day, as it's not worth what you have to pay for it.

A few years back you could even fly from Singapore to Tioman with Berjaya from Seletar Airport, but they cancelled the route meanwhile, if I'm not wrong.