Sorry not to respond last night. We live in Chiang Mai Thailand 7-9 months a year. This last fall we took a drive through the Korat Plateau and along the Mekong. It was really a totally interesting and beautiful trip. After many years of going to Thailand for business, etc., it is nice to be able to wander arround on our own pace. Almost every place you stop has something of interest.
Two web sights come to mind vis-a-vis Thai / Southeast Asian Archaeology.
U of Penn: http://www.sas.upenn.edu/~csherman/
U of Hawaii: http://www2.soc.hawaii.edu/css/anth/projects/banchiang/banchiang.htm