Show up plenty early.
Yes on the snacks and water.
Find, and become friends with the driver whose route you train on. Their wisdom might keep you alive through your 30 days.
Bring food/money/drugs/whatever to your preloader. (My job) Pay them off. They can make the difference between pass and fail for you.
Get ready to hustle. High failure rate, cause a lot of people can't handle it.
Don't hit nothin' and don't let nothin' hit you.