New York Pass

I'm going to be on the New York Explorer in a few weeks time.

I arrive the weekend before it starts so I will have plenty of time to explore New York by myself before hand. I am intending on buying a New York Pass which gives free admission to many attactions over 7 days.

Is this worthwhile?

Should I hold back on any of the main attractions as I will probably do them with the rest of the group on the Contiki?

Would you recommend reserving a ticket to go up the Crown of the Statue of Liberty? I've heard that Contiki don't spend much time there so I could do this in my own time.

Any help would be appreciated.