when we went to the Arnold i bought 3lbs of lean turkey lunch meat and two loafs of Ezekiel bread; pre made all sandwiches the night before.
A box of metabolic drive bars (free shipping), 3 gallons of water and a bag of Oreos.
But if you don't have a microwave you are going to be very limited on your meal choices. Flavored tuna packets, salmon. Pre-cooked shrimp, crab meat; in a cooler of course.
I used to race ATVs nationally, year round and i lived in hotels every weekend. We would bring our own microwaves. You can get a small cheap one for $50 at walmart.
I would be freaking out too but there are most definitely ways to make this work. Good luck...