Pack a mini-dustpan and broom to clean the coops. Bring some shavings with you if you have extra room. You can generally find bags of shavings to refresh the coops at the beginning of the week but they may become scarce latter. The coops sit on wooden "trays" on which the host clubs may put a small handful of shavings. This isn't nearly enough to keep a rabbit clean for a week. The animals need a good couple of inches of shavings so they don't become soiled from sitting. You may reserve insertable wire "risers" or bring your own as some wooled breeds do. You can find out the cage size from the host club. The rabbits will sometimes kick or dig the shavings out of their coop or the simple act of resting in the center will shove the shavings out the sides. To help combat this I put thin cardboard or heavy construction paper on either side of the coop. This requires some extra work bending and folding to get it thru the surrounding wire but I feel it is worth it. The purpose is 3-fold. It helps keep the shavings contained so you can at least shove it back into the coop. It keeps other rabbits from spraying yours and maybe provide a bit of prevention if a neighbor sneezes. Oh, and it helps lessen bunny squabbles when the bucks take a dislike to each other and try to start a fight.
Cleaning coops while judging is going on is frowned upon by the breed clubs as it makes it harder for the runners to get around. It is ideal though for the owners because the rabbits are out of the coops making them easier to clean. Generally you have to drag a bag of clean shavings and an empty one for the soiled better from coop to coop. Take care not to spook the rabbits in the bottom coops when dragging these bags by them.
It helps to have a small container to dump dirty water from dishes as you simply can't dump it on the floor. I prefer to buy a gallon jug or two of water to bring with me than use what comes out of local taps.
Rabbits are displayed by class, so unfortunately, your animals will be spread out through the breed's area. While all your solid senior bucks will be cooped in one row, the solid junior does may be two aisles away. Generally the cooping is three tiers high, numbered vertically. So if you have 3 bucks, coop 100, 101 & 102, one may be on the bottom tier and the other two will be a top tier and second tier. I don't know of one ARBA member who doesn't prefer the sensible idea of cooping all an exhibitor's animals together in one place, per breed of course. But ARBA demands the host club set up as a display by class and not by what makes sense. Sigh.... The clear benefit is that an exhibitor could feed and clean all their animals in one stop, instead of hop-scotching over other exhibitors with all their supplies. Plus a potential buyer can see all your animals in one contained section, the ones for sale, the ones not and how they may all be related to each other. Getting a clearer picture of consistancy and quality to make better decisions is helpful.
Use your exhibitor tag to write your coop numbers on the back so you can find your rabbits quicker. Some conventions use the exhibitor number instead of by exhibitor name alphabetically.
Hole punch your business card, put on a shower ring and hang on your For Sale animal's cages. While on the subject, mark everything you bring with your name and cell phone number so nothing goes missing.
Many exhibitors use cute-sy things to mark their coops to make their own rabbits easier to find. It might be a colorful ping-pong ball, tags, used CD's and signs. This does help, just be sure to remove your junk when departing so the host club doesn't have to do it when breaking down coops.
If you end up with a scratch cage, keep your feed, water and other supplies in it.
For feeding I use a round plastic tool tray that has three divided compartments in it. I put a baggie of grain in one, a baggie of oatmeal and baggie of striped sunflower seeds in the other two. I can easily carry this from aisle to aisle. The handiest thing to carry a water jug, feed and hay, cleaning supplies and grooming kit is one of those rolling wheeled crates.