Late spring is the sweet spot for the Pacific Northwest coast. The winter rains ease up, the crowds haven't hit yet, and you can actually find a decent place to stay near the water. Driving down highway 101 through the redwoods and rocky beaches is the kind of trip that clears your head.
A typical road trip here runs about $1800 for gas, food, and places to sleep. Spreading that cost out over time makes it manageable, but you have to plan the numbers before you pack the car.
That 0% period is a deadline, not free money. If you still have a balance left when the 15 months are up, interest kicks in on the whole original amount.