Yes. They are free but they're also in high demand. Check the website at 6:31AM on the day you plan to visit and same-day tickets may be available.
Yes very hard to just walk up n get in
Yes you do.
Yes, you need a ticket.
Tickets are always free. Advanced tickets are offered the first Wed of the month. The ones this Wed are for April.
Thanks! Your answer is awaiting moderation.