South East Asia is a herculean task. Start with India - trek in the Himalayas, Meghalaya, chill out in the backwaters of Kerala, go for a desert safari in Jaisalmer, attend the evening aarti in Varanasi. Myanmar is an interesting though offbeat place to go backpacking in. Thailand is a must visit. You can do a quick Laos-Vietnam-Cambodia thing too.
Remember to get the required vaccinations done. almost 5 years ago