Here's a link to a very interesting article about Jim Thompson. In 1986 I visited the house, which is now a museum, where he lived in Bangkok. In 1993 I visited the Cameron Highlands in Malaysia, the beautiful region where he disappeared in 1967. (However, I didn't visit it because of the connection to Jim Thompson.) Having walked in that area, I agree with the people who say it would have been difficult for him to get hopelessly lost in the "jungle" there.

http://news.bbc.co.uk/2/hi/asia-pacific/6484761.stm