Mr. Me said:
My opinion is that many guys need to run a tighter ship. This situation of not knowing when you'll be free until practically the last minute doesn't lend itself well to not being flaked on.
Why don't you do this: Email her now with a definite time/date to meet, making it for some time you think is reasonably when you may be able to make it. Don't tell her that it's iffy, though. The idea is this: I'd rather have you cancel out at the last minute rather than her. And I want to see what her response is. We want to see "Yes" and not any variation of "No", such as "I don't know what my schedule is yet", "let's confirm", "My kitty cat needs a leg cast removed", "My mother may come into town and I haven't seen her in ten years" or "I'm moving that day" or no response at all.
Hopefully, she's not lying to you about that. She could be and that's why she was vague with the "call me when you're around" instead of trying to help you figure out when you could meet her, such as her saying to you, "well, perhaps we could meet during your lunch break?". Exchanging photos ought to be something you do way up front. In fact, you should have photos of yourself online if you're doing the online dating thing.