Personally, I like contacting them a week or two or even longer initially.  once they respond and a date is set  don't worry about it.  A couple days before I send another email.  They get pretty busy with clients and some touring so don't expect them to sit on their keyboards all day.

She could be busy with any number of real life issues or just taking some time off.  Some better questions for you might how much you want to see this particular provider and how much time you have to contact someone else if need be.

Before you head out west. If you are leaving in short order, then contact others for potential backup.  If the trip is a ways off, relax many ladies are very busy with lots of stuff PLUS the hobby.

... is at the end of when I'd expect a reply so I'd suggest you followup with another contact using the method you did originally. Then, also send her a TER PM and a P411 appointment request and mention you had tried to contact her by other means. If she's popular, she likely gets lots of inquiries with a small percentage of them actually being earnest. If she's someone that you're just somewhat interested in seeing, you've waited long enough and should move on. If you post this same question on the Vegas TER board I can guarantee you that you'll receive several tempting proposals within just a few hours of your post.