Does anyone know of a beautiful park

Caumsett State Park in Huntington is on the water I think and allows ceremonies if you get a permit. I have no idea about parking. Here is the number to Caumsett:
(631) 423-1770

Thanks

You might want to look into the Cold Spring Harbor or Huntington Bay area. They are closer than Caumsett, right on Northern Blvd (Rte 25A). I don't know how many cars you would need to park, and I'm not really even sure what the parking situation is up there, but I've been up that way to take pictures of sunsets at some small parks along the water there and it's really beautiful in that area.

You might also want to contact some local photographers and ask them for some suggestions. Hopefully if you explain your situation, that you are planning from out of state, they may be more than willing to pass along some more ideas and tips.