From the Military West Street entrance, the Benicia State Park loop is a moderate 4.75 mile run/walk with a nice mixture of flat grounds and rolling hills. You can choose between the dirt trail or paved road, there's also plenty of room for both cyclist and hikers on this trip.
The trail will take you along tidal marshlands until you reach Dillon Point – where you can catch a great view of the Carquinez Bridge and the straits. About 2 miles in there is a a rest area and native plant garden.
There are several side trails you can explore while on this trip. From Dillon Point you can follow the Bay Area Ridge trail across the Carquinez and into Crockett, or from Military West its a short trip to downtown Benicia.