Sounds about right. FYI the park is about 10 minutes from the 12th Night site. Continue south on I-5 past Santa Nella. Head east on 152. Turn right onto back roads following signs and directions.

Not that it will bother you with your mountain riding experience, but the park itself is foothill rolls, not farmland flat (It's one of the areas we've looked at for holding a war). Sounds like the bulk of the course will be out in the farmlands with starts and finishes in the park. Traffic is very minimal around there and drivers are largely courteous (at least to ponies and carts).