I booked 2 return tickets to Phuket using the 24 seat VIP aircon bus last year (August time). Collected from the Clocktower, Hua Hin at 9.30pm (coach starts out from Bangkok) arrived in Phuket about 6.00am next day.
Good comfortable reclining seats, movies, (all in Thai), drinks, and snacks, stop off for food on the way (price included), then lights out for an easy slow drive down to Phuket to arrive first thing in the morning, slept pretty much all the way.
Costs if I remember correct was about 3,000 Bht for two return tickets. Very easy and relaxed way to arrive. The return did put us back in Hua Hin (Clocktower) at 3.00am though (arrives Bangkok 6.00am). Not many taxis about to take us home.
Booked tickets through an agent opposite the bus station by the level crossing on Chomsin Road. The agent was even at the Clocktower to meet us, give us our tickets and wait for the coach with us.
On arrival in Phuket Town, watch out for the taxi drivers, after a few coffees we approached one to take us to Karen Beach, he wanted 1,000Bht, he asked my wife why I was laughing so much, she explained we’ve just come from Hua Hin for 750Bht and it always makes me laugh when locals think we are Tourists and try it on. Settled on 200 Bht and I gave him 250.
