The Then and Now series and the last few photos of Sunset Park in decades past have been some of the most popular posts on this site. They've also brought out some other history buffs around the neighborhood (and in farther flung places).
I received a lovely PDF link in my inbox from a neighbor. The PDF is the 1902 Annual Report for the Parks Department. It details work done on Sunset Park, as well as the acquisition of the space from 43rd to 44th Street - which completed the square footage of the Sunset Park we know today.
And here's the "rustic stairway" leading up to the park from 5th Avenue.