Bronco Canyon and Schoolbus are far away from the others. Schoolbus really isn't worth your time IMO. Bronco is good but it takes a minimum half day to get in, run it, and back out. Longer if there are breakdowns as it is far away from pavement.
The other trails are relatively close to each other, with moonrocks in the middle. Here's my suggestion for a kick ass day.
1) Dolores
2) Billy Bobs or Twister (might be possible to do both)
3) possibly run another good trail in the area that is un-named/semi-secret
4) then head to Moonrocks and either pick up dinner on the way or have a BBQ there and play on the rocks.
5) if you are itching for more, do Steve's Loop as an evening or night run
There is another short trail in Reno called Budweiser. Its right in town though, not in the immediate vincinity of the others.
If you are really endevorous, you could then run Bronco Canyon on Saturday before heading home. Bronco would make a good finale to a good weekend if you have the time to not be rushed to get through it.