Dump any expectations. In fact, this request for f2f would be a red flag for me (based on my experience / my sitch).
If you are concerned she is going to get mad at you for not being able to schedule f2f around her, then I would say not enough has changed.
Is she asking you to go for coffee or is she telling you she wants to have a f2f with you? The difference might be considered (former) friendly get together / (latter) business meeting (possibly so she can tell you to your face that you are to NOT comm with step kids; even if they initiate).
Anyhow, all I would say is, do not get all excited about this f2f and think that if you cannot squeeze your schedule to fit her in, that you will destroy an opportunity to reconnect.
If she really wants to reconnect and begin a friendly R with you, then all you need to let her know is that you are extremely busy, the best time to get together would be (make one or two specific times / dates as options), and look forward to chatting.
