I am a veteran closer, and I have a list I use to keep track of everything, including roughly what times everything should be done at. Closing always varies store to store, but I can link the list if you would like!

It's almost certainly slower than the mornings, but that's replaced by the tasks you need to get done. Whether you get out early, on time, or late mainly depends on your Shift and whether you're staffed well enough or not. You don't need to do any prep. Just be proactive about asking for the next task if you ever don't know what to do with yourself. Ask if you need clarification on an instruction, or if they tell you to prep something and you don't know where to find everything. Your goal is to do everything as quickly as you can do it well, but emphasis on doing it well.