It is recommended to rent a car to explore the city and the national park comfortably. Car Rental cost is around $50-$80 per day depending on the car type. Expect almost 2 hours of driving from Chico to Lassen Volcanic National Park. There is an affordable Amtrak bus that departs once daily from Chico to Redding, which is the nearest city to Lassen Volcanic National Park. The bus ride takes approximately 3 hours, and the cost is only $20-$40.
If you have an additional day or two, explore the historic Gold Rush towns like Grass Valley or Nevada City. If you're into wine, spend a day in the Sierra foothills in northern California wine country. If you're on a budget, Nash's Organic Produce has affordable meals and snacks. Try to visit during the Fall season when the leaves are changing, and the temperatures are perfect. For the art lovers, spend some time exploring the downtown farmer's market and discovering the local artist's galleries. If you have less time, skip the national park and opt to hike a portion of Lower or Upper Bidwell Park.