My wife and I spent 3 days and 2 nights at Rio Costillo and really enjoyed our time.  We are typically dispersed campers, so paying to camp is a bit of a departure.  The fee to camp has increased to $30 per night, but we decided to give it try.  It was probably more about what we didn't experience that we enjoyed the most.  There is NO FIREWORKS permitted and NO ATV's permitted.  Thus, a pleasant and quiet camp trip.  There have been no recent fires in the area, so the views were beautiful!.  Not sure how many head of cattle roam the park, but they could care less about you and do not pose any threat.  The sites are spread apart so much that it feels like dispersed camping.  Portable toilets are close to all sites, but no running water.  The lakes were closed at the time of our visit (clearing the road of fallen trees we were told).  Most of the sites were close to running streams of water, though we only fished in the Rio Costilla outside the park entrance.  The fees are $30 per vehicle/night and $10 to fish per person per day.  No fee to fish in the river outside of the park, only a NM license or out of state permit.