South East Asia - Plans for a Four-Week Trip

On the 4th of November 2008, I will fly from London (current abode) to Bangkok to commence a 4-week trip through Thailand, Laos, Vietnam and Cambodia. With two weeks to go, tickets are booked, visas acquired (for Vietnam), and inocculation has been suffered. First stop, three days in Bangkok. Then, fly to Vientiane to spend approximately 5 days in Laos taking in 'its people and the intangibles of the easy-going air'. After which, fly to Hanoi, Vietnam and travel south to Ho Chi Minh city over a 10-day period. From there, fly to Cambodia (most likely taking in the sights of Phenom Peng, Siem Reap and Angkor Wat) for 3/4 days. The final week of our trip will be spent around the islands of southern Thailand in the pursuit of relaxation. My travel companion will be Anne, my mother, a keen traveller and an expert in all things medical and botanical.  Soon I will compile my 'to bring' list. First step, to consider how I can stuff my rucksack with what locals need.