Hi Andy!
I usually shoot for 3 am - 6 am.....but 6 am will still work, just be aware that the tourists start milling around again about 7 am (8 am on weekdays). Get the chips you want the most at 6 am, pick up any others if time allows. I try to get done alittle before 6 am so I can still catch a $2.49 steak and eggs breakfast special before it ends (at 6 or 7am).......snarf!