Meet at the Fish and Game parking lot on Buchli Station Rd at 9:00 am. From Napa, take Hwy 121, turn left onto Duhig Rd, then turn left onto Las Amigas Rd, then turn right onto Buchli Station Rd. Follow the paved road to the END sign, where the road turns to gravel. Follow the gravel road and cross the railroad tracks to the parking lot. There is a bathroom available, but it is pretty gross. There is no water available.
The bike route will follow the levee roads. The route is pancake flat. The levee roads are hard-packed with a few spots of small pebbles or gravel. A hybrid, mountain bike, or something with wider than normal tires would probably improve comfort and stability. However, they are not mandatory. The route has been ridden on a road bike with 25 cm tires.