West Coast Number Theory 2018 will be held at California State University, Chico. The conference will take place on the university campus which is located in downtown Chico, walking distance to restaurants and coffee shops.
See update on the California Fires.
If you are traveling by plane, you can fly into the Sacramento airport and take the North Valley Shuttle to Chico. The shuttle ride is about 1.5 hours. I would not recommend any other shuttle service. If you prefer to have a car, picking up a rental car at the airport is also a reasonable option — just take highway 99 north all the way there. There is a train and a bus but the travel time may be significantly greater. Uber is an option and usually costs about $100 one way.