It is possible, but you'd have to be lucky to get there in one day. There are buses, and you would have to change about 20 times, then you would have to walk the last 3-4 miles in. Rent a car. It's a nice drive. And you can enjoy other sites along the way. Taxi would be too expensive. Maybe you can hire some bonsai buddies in the Long Beach area who could let you car pool there with them.