By Train
By Train At Bangkok railway station (Hua Lamphong) you will find a color marked ticket counter on the left side of the counters. There you can buy the combined tickets. You can choose your mode of transportation - 1st or 2nd class, seat or sleeper (recommended) and A/C or Fan.
Price for a combined ticket is app. 800 Baht for 2nd class and app. 1,200 Baht for 1st class. You also can buy just the train ticket. Tickets for a night-train can be booked at Bangkok Railway Station and many travel agencies in Bangkok.