We just spent 2 days XC skiing at the Mt Shasta Nordic Center and thoroughly enjoyed it. It was not very busy despite it being a holiday weekend so we never felt crowded at all. They have a good range of trails which are very well marked and easy to find. We stuck to the Green beginner trails and the Blue medium trails. They provided a good variety of terrain and great views of Mt Shasta itself. We did not venture out onto the Black expert trails so can only speak about the beginner trails. The staff (the center is a non-profit) were very friendly and helpful. We had a great time overall. There is no food for purchase there, just a warming hut with some tea/hot cocoa so make sure to pack a lunch