The bus from Phuket to Bangkok leaves from the bus terminal located off Phang-nga Rd, not the central market area. The bus terminal is also where you would catch a bus to take you to Surat Thani and then the train on up to Bangkok. Both of these trips, by bus or train, are overnight and get you into Bangkok pretty early the next morning. There are regular mini-bus trips from Singapore and Penang and other sites in South Thailand which are reasonably priced but only recommended for the young, the brave or the hungry for adventure. They tend to be overcrowded and built for small Thais not larger farangs.
Vendors ply their food wares at stops as well as cold drinks.
The train departs from Hua Lumphong Railway Station in Bangkok then to Surat Thani, where you transfer to a bus or fly direct to Phuket. Krabi, located about 160 km from Phuket, has a domestic airport just opened in the summer of 1999. Air Andaman has recently begun operating daily flights between Phuket and Krabi, with schedules dependent on the season and weather conditions. They also operate a Phuket-Surat Thani flight daily. Koh Samui does have an international airport.