Ok, I took a look at some places last night and I'm leaning toward the Pima Canyon Trailhead entrance off of 48th & Guadalupe. There are a couple ramadas and picnic tables (it's not as crowded as the north entrance).
Benefits: Of the three choices, this is the closest option for most of the group. The trails are pretty wide and flat, and it will get darker the quickest here as the sun starts setting behind the west side of the mountain. It's also the closest off the freeway, and will be easy for Roger Sully to rendezvous with us from his Mesa location.
We do need to get there before the gates close at 7 pm, otherwise it's a bit of a walk to the ramadas. The trails close at 11 pm, so no worries there.
Pima Canyon Trailhead Entrance
I went south of there to the Ahwatukee Foothills entrance off of Chandler Blvd and really like it, but it's probably not the best option this time around since it's a bit of a drive once you get off the freeway. Additionally, there are no ramadas or picnic tables (see the turning loop on the aerial view).
Benefits: There's plenty of parking on both sides of the gate, and everything's very close to the road so you don't need to worry about getting there before the gate closes at 7. On the way back to the freeway, I noticed vast stretches of land off the south side of Pecos Rd that would be fun for high-powered throwers. Maybe something to consider for a future and weekend gathering?
Ahwatukee Foothills Entrance
I didn't get to the north entrance last night, but I'm fine with this option if it comes down to it. It's also a bit of a drive considering most of us will be coming from the east Valley during rush hour. As I recall the trails are steeper here and it's another good option, but may also be better on a weekend night when we have time to enjoy the area.
Benefits: It's an awesome place to watch the sunset once you get to the top, and there are lots of ramadas and picnic tables. Brlux may have more to say here.
South Mountain North Entrance