Rockport park has a network of singletrack built around wide cross country ski trails. groomed trails are ski only during the season. The single track parts are signed for bike and snowshoe, just jump on the first one you see and explore. From the NE trail head off the circle there's one that crosses the main trail just a few yrds in, that goes either way and makes a loop and connects to others. Most of it is bench cuts on fairly steep hill sides around the streams in the area. It's generally not to difficult technically but there are some climbs and descents. very nice.