I love to travel but haven't been to Indochina. There is an organizaiton, AbleData that is funded through the US Department of Education that has a wide variety of travel resources listed. You might check them out -
They list a group - EasyAsia - that looks very thorough in their travel assistance. Since I have not worked with this agency, please be sure to check them out on your own- maybe look for some online reviews about their travel help.