I'm in Atlanta, which is probably almost as bad as being in NOLA in terms of snowboarding (though I can get a fix by driving 3.5 hours if I don't mind riding down the bunny hill at Cataloochee).
A night session after an all day session is pretty tough. Even if you manage to not collapse and go home early during the night session, you'll end up the worse for it the following day.
IMO, you'll be doing ok if you can stay disciplined enough to wake up, get first chair every morning and stick around till the lifts close each of those 4 days.
Important: If you have never been to Breckenridge, then prepare to have your ass whooped by the altitude difference (ESPECIALLY coming from NOLA).
Take it very easy your first 12-24 hours after you land. Hydrate yourself more than normal. Take it easy on the alcohol (might be better not to booze at all until the 2nd night or so), and if you do ride that first night in, don't push yourself too hard. Even if you don't get headaches or short of breath, you will probably feel off... almost as if you were slightly depressed.
I hope the snow gets better for your trip. I haven't been to Breck in many years, but you can actually get a reasonably priced lunch at Imperial burger, and the the mango/pork burrito at Mi Casa is the yummiest meal I had there.
Take this to the bank. I visited Breck from Florida last year and even though I stayed hydrated before and during the trip the altitude got to me for the first few days. As far has hitting Keystone for a night session, it still counts as the same day on your pass. However as Tarzan pointed out riding Breck all day then hopping over to Keystone at night will kick your ass unless you are in tip top shape. Besides already being tired from riding all day there is some downtime between when Breck closes and Keystone opens for night riding where your muscles will turn to stone. On the gondola ride up at Keystone I thought it was going to be epic because it was a beautiful night but ended up getting my ass handed to me and limping home after my first lap. My wife was much smarter to hang out in Starbucks with her laptop....lol