I was up at Middle last Sunday and Monday on foot with my dog. Sunday started out pretty nice and then the storm came. Monday was a complete white out and was back to the road by noon. As far as the road goes. If you have a 4runner or something comparable, you would have been able to park at the trailhead. Anything with less clearence you would have needed to park at the 10 mile mark. TH is 10.5miles. It was snowing at the TH, but nothing too bad. Basically, it was no problem getting into Middle/North Sisters. Don't know anything about 3 creek.
HTH
Dave