All this. When my kids flew to Florida, the gate closed WAY before the plane took off. Print your ticket at home, don't trust their machines to work or anyone to be at the gate to scan your code. Be prepared to get all up in someone's business if they don't accommodate you; they don't like negative PR.
Don't trust that they'll feed you when they say they will, and always have cash on hand for meals and a hotel room in case they have to reroute you. Call your bank and let them know you'll be traveling, but also don't trust them not to push a wrong button and leave you without debit access.
If you can get away without checking any bags, do that. Never put anything in a checked bag that you can't live without for a week.
Oh, and never fly Spirit Airlines.
(I really hope you're not flying with Spirit Airlines. I didn't sleep for two whole days both times my kids were in transit, because there were that many issues.)