Renting a car in the US is the most convenient.

The receptionist noticed our luggage and suggested upgrading the vehicle for an additional charge. After some negotiation, we agreed to pay an extra 300 dollars. When we saw the Chevrolet in the garage, it looked as big as a tank, which shocked us. With the help of the garage staff, we switched to a smaller Ford Explorer of the same class. Although it's an SUV, it felt a bit underpowered on inclines.

Picked up the car in San Francisco using the self-service machine, which was quite convenient. However, you need to enter all the reservation details again, so the counter might be faster. No one tried to sell me insurance.