You need to transfer a minimum of 20 points when you first order the card, then can transfer points to the card over the phone or through Chase's website. The additional transfers need to be a minimum of 10 points.
What I would do is order the card now with the minimum 20 points, then call or go online right before you leave and transfer what's left or what you think you want to use on the trip. It'll save you from having to make the trip to DTD to get the card if you weren't planning to go there at the beginning of your trip.