Yeah, I know there are many, far more “mobile” people than me. And I completely agree about not carrying an open file around on a laptop. Encryption might help you there.
If I were to store such information remotely, I’d put it on a machine I own (or at least control), where the only access would be via ssh. I avoid things like Dropbox – I don’t trust them – but I’ll admit that it’s mostly a personal aversion.