I did the same with my girlfriend some 23 years ago, and flew to NYC. I wanted to propose on the top of the Empire State Building, but it was January and so cold that I bottled it! The moment seemed to have passed, but I eventually did propose under the least romantic circumstances possible, a university halls of residence in Chelmsford, Essex.

Fortunately despite all she said yes, and is still my wife!

Best of luck to you, and I am sure it will live up to expectations!