Some things to consider:

1. Moon phase. March 25th is a waxing crescent, which should be great, but if you change dates and end up going during a full moon, then there's going to be a big spotlight in the sky all night long. So if you want to see stuff like the Milky Way, look up a moon phase chart and time your trip appropriately. New moons are ideal. IIRC waxing half moon rises late so it's good for evening viewing while waning half moon sets early so it's good for early morning viewing.
2. Dress warm. Even in the summer. It's cold at night, especially when you're sitting still all night. Layers and blankets are your fiends.
3. There's two viewing areas, separated by a road. There's a parking lot on one side of the road with a viewing field and some seats that are protected from the lights of the lot and the street by a berm. That area is open to any visitors. The other side of the street is only for people camping overnight in the park, and it's the side that has bathrooms and shelters to block the light.
4. The people coming for stargazing I've found to be very friendly and welcoming, but I found the locals to be less so. Surrounding areas have giant signs saying, "This is GOD'S Country" and the like. I have been incoherently yelled at in the past just for looking like I'm from the city. Also the surrounding counties - Potter and Tioga, etc, are known for being one of the state's centers of white supremacist activities. So just be warned and be careful.
5. While I've found the cell reception at the park itself to be pretty good, the surrounding area is a giant cell phone dead zone. You'll be struggling to find a single bar. So bring maps, as in the paper variety. Plan for a low-tech weekend in general. And don't whip out your phone at the park at night without a red filter screen protector or something. Red lights only in the park.
6. Have a backup plan in case of bad weather.