Decent betFirst week in April can be some of the best skiing at Copper. Over the past 5 years there's been two fantastic Aprils (2001, 2003), two pretty good ones (2000, 2002), and 1 that was ..um.. marginal (2004). Regardless, I think 100% of the terrain has been open the first week of April each year. So overall, you're likely to have good conditions. I've had some wonderful powder days though.. bright blue skies, skiing in a light jacket, and busting through 18" of fresh snow.
Also, when you consider the altitude and exposure, Copper has the best conditions in April compared to Breck, Keystone, and Vail. I'm actually amazed Breck stayed open as long as it did last year. A Basin still trumps it though.
Last year Copper expanded their "Sunsation" event to all three weekends in April. They brought in live bands for Saturday and Sunday - free. Not sure if they'll do the same this year, but it's a good event.
(720 Granite St? Drive by there every day..)