If I arrive at 4:45am, how long before shuttle for. 545am flight?

I have never waited more than 15 minutes for a shuttle, but that seems to be cutting it awfully close only leaving yourself 45 minutes.

Unless you have TSA pre boarding in the fast lane that you get there earlier than an hour before your flight you need to be at the gate 30 minutes before boarding. That early in the morning the shuttle bus will follow you to the parking space or show it to you and pick you right up

You have to call and book, tell them what time your flight is and they'll tell you what time to be there. Pretty sure you should be there at least 2 hours ahead of your flight