We have visited Big Sage a number of times and it used to be a nice little campground set on the shores of Big Sage Reservoir. We have caught largemouth bass and crappie in the reservoir by the campground and we have launched our small boat and fished the upper reaches. Sadly, in the last few years feral horses have shown up and they are tearing up the campground and they are aggressive. There is horse manure everywhere.
My wife and I stay here quite often. It is a nice campground on a beautiful lake. There is a trail that circumnavigates the entire shoreline and is some of the best birding on the Modoc National Forest. The trout fishing is mediocre but can be good at times. The crawdad fishing is really the ticket however, lots of them and they are big. only downer is it is a fee site.
This was a neat campground right on a little creek. Too bad the USFS closed it.