Get a gigantic water bottle. Mix in some whey and a fat source like nut butter with water or milk. Sip on it throughout the day between meal breaks. Though you'll probably wanna just stick with water if you want it to make it a few hours.
Carb up on something easy like rice cakes. I know whole foods sells some rice cakes that pack like 18g carb per cake. Really easy to put a few of those away.
Get a plan down on paper. Set out how many grams of protein/fat/carbs you want on the day and make yourself a plan and set it all up the night before so you can actually visualize everything you'll have to put away for the day. Will make it alot less stressful.
Oh and canned salmon, or tuna. Buy yourself a cooler.
Your training sounds just right.