From Singapore to Thailand I suggest you to travel by Express bus. Its faster and comfortable. Aeroline Bus Maybe you can have a look at this bus company. And from Kuala Lumpur, you can buy the express bus ticket opposit the Pudu Raya (main bus station). Take Konsortium Bas Ekspress. They are on time and comfortable. The bus will take you into Hatyai stopping right in front of Lee Garden. From there you can take train or bus to Bangkok. If you need to go by bus, tell the tuk tuk driver that you need to go to บ.ข.ส (Bor Kor Sor) the bus station. Its better you write it down and give it to the tuk tuk driver. Bus is faster than train alot. Bus will stop you at Sai Tai Mai in Bangkok where you might need to take Taxi into the city. Get into Bor Kor Sor to buy the ticket. Normally the tuk tuk driver will stop you opposit the Bor Kor Sor and there will be a lot of agencies. The people of the agencies will start to call you into their premises. They are selling the express bus tickets as well but not belongs to the government and might be dangerous and totally not comfortable (Something like the Khao San Road Buses). Just say No and cross the road into Bor Kor Sor. There are a lot of buses companies in Bor Kor Sor where the sellers are wearing the uniform. I suggest you to take Piya Tour (0 7442 8972) or Thai Doen Rot (0 7442 9525). If you need to go by train, you can take tuk tuk or just walk there. Its around 10 minutes walking by foot. Ask around for the direction because the tuk tuk will charge you more than what you suppose to pay i guess. There are several trains to Bangkok depends on what time and what kind of train you would like to go on. Here's the web of the State Railway Of Thailand From Bangkok you can take eaither bus or train into Laos. I am not sure if you want to enter Cambodia or Laos first. Well, there is train into Laos now from Thailand. From Hualamphong station, take train to Nongkhai and into Vientiane of you are visiting North of Laos first. If you are visiting Southern Laos, you can take bus to Chong Mek in Ubon Ratchathani province from Mochit bus station. Not sure if there is a straight bus to Chong Mek but if there's not, take bus to Bor Kor Sor Ubon Ratchathani first and from there take another bus straight into Pakse. Well, if to Cambodia by land, take bus from Mochit to Aranyaprathet and from there, take a motor taxi which to the border and enter Poipet, Cambodia. Well, there are a lot of scams over the Cambodian side... You might not want to pay extra for the visa upon arrival. I suggest you to get Cambodian Visa at the embassy in your country. You can also get to Aran by train which is cheaper and slower but can enjoy the countryside scenery. Good Luck. 