For a parent, being in two places at once is an acquired skill. When the child is small, you don't need it, because she's always with you. But sprouts have a funny way of flowering and asserting their independence and separateness, and pretty soon you need to be the spirit companion of the 8-year old going to the corner store, and then of the 11-year old on a sleep over and then the 13-year old on a class trip out of state. And then the 16-year old driver. And then they really leave.
The trick to dual locality is to learn what the offspring are doing without seeming to imply that you either have a right to know or that you're trying to control the activity. Cautious questioning, occasional visits, and expert between-the-lines reading are required, coupled with a healthy ability to visualize. It's hard to visualize Julian, because mostly what I seem to conjure is him unconscious well past noon. Perhaps because he is in a "safe" environment--small college town--and what he is doing is "normal" I haven't felt the need to lock onto him. I don't need to visualize what I already understand.
Nga Jee on the other hand is tricky-- I mostly visualize her sailing off some western cliff in a hideous bus crash; not conducive to trust in your grown child, or for that matter to a good night's sleep. Four days tracking her on a daily basis in situ as it were has helped hugely. I understand what she's doing and who she's doing it with. I am awed by her ability to function in this demanding world. I think that for Julian, college has delayed this for me. Next year I will need to learn to visualize him from scant clues, as he starts in on a life on his own, in a way that college doesn't offer.