Coastal xpress runs to 10:30pm - It is not recommended to ride bikes at night more so because of the condition of the road. At night it is difficult to see pot holes and such if you are unfamiliar with the road North, but many bikes do travel the road at night. It is strongly recommended that you take a good flashlight. The road up to Journeys end is fairly safe - common sense prevailing.
Taxi's are available always and easy to find in town and the bridge booth closes at 9pm so you won't have to pay the bridge fee.
Also, if you start walking toward the bridge you can usually hitch a ride on a golf cart heading North. Most will let you jump on if there is room.