Yeah, I'm in the same boat as you. I doubt many records of my family were kept post-Cultural Revolution, and my parents don't know very much about it because their parents didn't tell them very much.

Personally I've always found genealogy to be a pretty white-centric activity (though that's fine). I think history is interesting, but I find it kind of strange to trace genetic makeup, especially since my parents basically did "start again" after immigrating. For me, the family that you make is more important than bloodlines.

Also trips to Vietnam is a good idea IMO. I've travelled to Shanghai consistently over my lifetime and while I don't feel "at home" there or that I belong, there's definitely a connection to the place.