Yes Jon, we could enter the park from the Imagine mosaic place.
There is also MoMA, Met, International Center of Photography, Madame Tussauds if you are interested.
You can book the Empire State Observatory in advance if you do not want to wait in the ticket line. -
https://www.esbnyc.com/tickets/index.cfm?CFID=13256027&CFTOKEN=10879957
The time that I went to M Tussauds, they had a discount for AAA card holders. DOn't know if they still have that offer, but carry your AAA cards with you if you have it.