If your car is dependable I would have no worries. You only going for a 6K mileage trip. With high mileage, probably would not be a bad idea to pack 2 extra quarts of engine oil in the truck storage area. If I was too worry it would be flat tires. Make sure you have jack, lug wrench good spare, or plug kit and pump. Water, gloves, blanket, cell phone charger, credit card. Enjoy your trip.
If you've maintained your Prius and all fluids are good, tires good, brakes good, lights good, then you're probably good to go. Prius are notoriously reliable. But beware! Flat tires always occur where there's no cell service. Enjoy your trip!