We used Tiffany Towncar last May and were able to have the driver pick us up at Jamaica. He could not come all the way to our room, but he parked at the circular driveway nearest our room, and we met him there.
All we did was call Tiffany Towncar the day before they were to pick us up and let them know exactly which section we were staying in (Jamaica) and the room number, so he could park in the area nearest there. It was no problem at all. All we had to do was get our luggage from our room to the parking area, but that was not difficult. It's much easier and faster than trying to have bell services pick up your luggage by a certain time, etc. I think we might also have given them our cell phone number in case he couldn't find us.