Yes! Come one, come all! Enjoy the ceremony. The reception, however, is private and by invitation only.
If you have received an invitation, that means you're invited to both the wedding AND reception. It's very important that those invited to the reception RSVP. If not, there won't be seating/food for you.
As much as we love kids, we would prefer you not bring them. Find a sitter and enjoy a moment to yourself. You deserve it!