Yes. You can.
call ahead and get the temperature in the caverns so you can dress appropriately
Yes, and if your are the kind of people that plan everything ahead, like I am, you can buy your tickets online, print them and present them in the gift shop. Even when you book for an specific time, if you arrive early and they are not quite full. You can go. Good trip and enjoy the view.
Yes, inside the gift shop.
Yes
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