In reply to Jack B:
I've no idea at all about walking or vf there, but 25 years or so ago I went skiing in Summit County, at Copper Mountain, Keystone, Breckenridge and A-Basin. That's just up the road from Denver, maybe an hour and a half driving.
I've had many happy grey days at Glencoe, but I can confirm that the skiing over there is, indeed, substantially better!
I suspect you might find there's a bit much snow for walking and vf there in March, too. (Although I'm not sure how reliable that is.)