With a vague setting, it should be important the feelings it creates; I personally like gardens (in an offhand casual sort of way) and forests, so when I want to make a more eastern- setting, I make a highlight of how they met under a cherry blossom tree or that someone had a chrysanthemum, and when I'm thinking about a more western setting, I'll pick something like roses and lilies; it's not that plants don't travel, but because the aesthetics of a place can be lynch-pinned with simple details like jasmine incense, silk curtains, and mosaic artwork on the temple walls. And even that isn't exclusive, but when you're focusing on low-tech items that have been present throughout history like bows instead of guns, the certainty of where/when becomes a mystery, drawing on impressions and feelings - something you can trick with mid-tech talk like someone rambling about internal combustion engines or clockwork timekeepers or, subvert outright by introducing, "And then So-And-So drew her lightsaber..."

I'm just saying, you can do a lot with low-tech stuff like picking the right kind of bird and wildlife to stalk your protagonist's journey, different kinds of environmental troubles (hacking through thick jungle undergrowth? trekking across a dry, dusty savannah?) and different city-specifics, like maybe the temple's partitioned by paper thin slide doors. I dunno. What's specific to the "Southeast Asian feel" you can sneak into descriptions of things and stuff?