I usually have the table all ready first thing -- and I take care of my DM station last. The last 30 minutes is usually filled with whatever I can do to make the game progress faster between encounters/chapters. This is when I am usually sorting through my monster and NPC figures to station them behind the screen for ready use. This is also when I usually discover that I do not have a particular monster figure and start deciding what OTHER monster looks close enough to fit the scene without causing confusion to the players.