You can't drive in at the WBC entrance if you're not staying there yet. If you try, the guard at the gate will direct you further down the road to the entrance of the Grand. It's just a short bit down the road further on your left. You'll pull in to a little traffic circle where you can unload your luggage (there will be people there to assist you and get it onto a luggage rack) and the lobby entrance is right there. The Grand's parking garage is just to the left. Since you'll only be there one night, it might make sense to pack a separate overnight bag and leave the rest of the luggage in your car to unload it later when you re-park the car closer to your unit for the week.