If you are at a festival, why cook or eat anything in the camper! Festivals are just MADE for food! Yum, Yum, Yum! No cooking, cleaning, dishes, or water needed!
To save your battery power, take an ice chest along for your cold food items (if you have any), just like you did when you tent camped. Remember those days?
Save your water for cat-baths. Use nothing from the camper that requires electricity (just like tent camping). Enjoy the festival, return to your camper just for sleep, and hit the festival again in the morning!
Hopefully, February is still not too hot in Florida. Considering the entire Eastern half of the country from Florida to Texas to Maine is under ice and snow right now, maybe, you won't need air conditioning at all.
You can live without electronics for 4 days. If you need to charge your cell phones, use the tow vehicle and plug them in there for a while. Take lots of deodorant!
I agree with the above suggestion... try a driveway camp at home with NO electricity for 4 days and see if you can do it. If so, you've got it all covered. If not, figure out why you need electricity .... and work on eliminating it. It's only 4 days! Even on survival shows, folks make it for 4 days before going nuts!
Edit:
Remember also, you can always plug the camper pig tail into the tow vehicle to get battery power from the tow vehicle to use for retracting slides, electric awnings, and electric tongue jacks if the house battery on the camper goes dead.