There are several other beaches within an hour drive that you can drive on to launch. Cresent Beach(just south of St Augustine), Peters Point in Fernadina(Van Dyke road), Amelia Island State Park and Jacksonville Huguenot Park(noth side of St Johns inlet). But you need to find if you need 4 wheel drive for the soft sand.
Anastasia state park(south side of St augustine inlet) has a nice launch site in the bay for sailing when the ocean is to rough.