I asked at our hotel about the best place to see the 4th july fireworks but nobody seems to know. It's only the second year they've had them on the Hudson. Best thing would be to go into Macys and ask. It's on 34th and 6th ave. The 4th july sales should be good there
You also mentioned rooftop bars. We had our Jubilee booze-up at Salon de Ning atop the Peninsular hotel. You won`t be able to see the fireworks from there though. It`s not cheap but definitely worth a visit for the experience (especially on a nice night)
Thanks so much for checking for me. It was supposed to be this year but has had to be postponed until next. I shall keep my ear to the ground whilst there. Hope you had a great time.