There were about 20 spots at the lake area it was a pretty location. There were a few spots open on a Thursday afternoon when we arrived. Seemed to fill up by Friday. They did put in porta potties when we were there. The road up is a bit rough. We managed it barely in all wheel drive vehicles but did get stuck for a bit at one point when we had to stop for someone on their way down. There were a few spots on the drive up as well. Overall good spot, at pretty high altitude. There was a bit of snow.
Definitely need 4 wheel drive and decently high clearance. I only saw Jeeps, 4 runners, and trucks. Rocky and steep at parts, it was pretty damn rough. Then if you go the back way to the dunes there are spots of soft sand and going through the creeks. Good amount of pretty sites. We found a site on a Friday at about 7pm. Highly recommend Medano Lake for a hike in addition to the dunes.