I've been doing this for three years, so far. But before the digital nomad phase I backpacked through most of Southeast Asia on two 4 month trips and another 1 month trip. And before travelling I worked from home for about 10 years...
For my one place, can I pick an entire county? Probably Thailand. Good infrastructure, great food, beaches, mountains, culture, nightlife, zany crazy stuff.
RE: Best places to go as a digital nomad in Southeast Asia