HI there, Welcome to Seattle! (any time soon). This park has three entrances 400 feet apart from each other. The "main one" is on the East side of the park. The one on the West side is the less obvious one, and with the third one right in between the other two. None have gates, with the East entrance being the more wider an obvious to see by googling it using the satellite option as the best way to notice the park features (pass the word to your group). There is a huge parking lot for free which makes more sense to define your meeting point in the main entrance close where the parking lot started. I have read a suggestion about meeting on top of the hill as a unique landmark, good suggestion. But (always a but), I have no clue how old your group is and maybe will be a better idea to meet on this "main entrance" and plan your sessions from there. The latest sessions, I'm presuming, are going to be the sunset ones with the one on top of the hill facing the sunset as the best point for it according to me (I'm a aficionado as well being doing photography there). My only concern would it be the safety of your group. So, be sure to have everybody together when getting darker and always suggest move as a group when moving around and most important when leaving the park assisting each other to be sure everybody is fine. This park is frequented by homeless people and the park don't have much of street lights inside. The homeless grow in number as the day closes, there the need to be aware of your surrenders. There is a gate to enter with cars to the park's lot. I have no idea at what time it opens and closes (check the park info). feel free to ask any other question. I have found very good information on this page and I'm returning the favor here, hoping you guys have a blast an those quasi-cloudy Seattle days that make the sky so wonderful for photography!!..

No fences around the park so I don’t see why not. But as with all parks, be cautious at night. The park is very open area, not much to hide around so you should be able to see who is there. It goes dark around five at this time of the year so not something you really need to wait out to ten if that’s all you are after. Unless there is something you are planning w your gf.