There IS no good skiing on the front range
Go to Vail.
Best turns are probably up north on Cameron Pass. long drive, but STILL beats the I-70 nightmare.
As mentioned, RMNP has some OK turns, out of Bear Lake and yes, the old Hidden Valley Ski Area. I HAVE skiied that, both when it was a functioning ski area (A LONG time ago..) and as recently as last year. This is the year to hit it, as usually about 40% of hidden valley is windblown dirt & grass.
Very northern Indian Peaks, just south of RMNP has some good turns to be had as well, was even in some older guidebooks.
some maps & quality time on Google earth can give you more ideas, or at least a lot of "recon" trips.