Your options are pretty limited this time of year, especially in Boulder County. With the floods last fall and the winter snow, most trails are closed until May/June. Heading further south opens a few options for trails open all winter. I believe China Wall stays open, and the Gulches
can be driven, and maybe Slaughterhouse. Yankee Hill is close by near Central City/Blackhawk, but this is a full on snow run as you climb higher and higher.