Last minute cruises usually mean a shortage of choices when it comes to staterooms. First, however, is deciding how far away you want to go (begin/end) and what you can afford, i.e. 3-14 days. If your son is old enough, sit down with him and get his input. Do you want total relaxation, history, warm weather, bears, iguanas, turtles, etc. There are many travel books (Rick Steves, for example, for Europe) that can help you. Late cruises with
DCL are usually more expensive than when they were first posted, contrary to almost every other cruise line. To your point, we just booked a cruise for next March (12 of us) and are scheduled for second seating, but are waitlisted for first. Closer to the date we will hound DCL for the move. Last resort we go to guest services when we board to see what they can do. Free meet and greets usually are first come, first served, so your chances of seeing a princess or character are the same as everyone else. Excursions you book when you make your final payment...I would recommend having two or three lined up, just in case. Some you can book on shore, but if they come back late, the ship might be gone. They will wait, within reason, for their own (DCL) cruises, but no one else's. Good luck!!