I think renting a vehicle is a more convenient option compared to buying one, especially if you're only going to need it for a short period of time. However, based on my personal experience, I'd recommend opting for a regular SUV or small car rental over using U-Haul, as I found their vehicle performance to be somewhat lacking. As for purchasing a car, not only would it be expensive upfront, but you'd also have the added hassle of needing to sell it before you leave. Overall, it seems like more trouble than it's worth.