Just like AV80R said, you can't always depend on getting a ride from the crew. They may have another leg, or they may have just a car for the crew to ride in (literally no extra room for a j/s and bags) or the hotel van may not allow a drop off at the terminal, especially if the hotel is the other way. It always helps to have a backup plan to get to your car, i.e. a cab.

Of course, if you can contact the crew early and tactfully ask their advice on getting to the terminal, most would be happy to help. I'm a commuter and I have no qualms about asking, and often have driven j/s crews on my flights to the terminal or their car.

Every ramp is different. If you have any particular ramp in mind, let us know and someone will chime in with info. Good luck!