A few days in Denver to hike – where to go?

There will still be lots on snow in March in Colorado. You would have to stay very close to Denver if you wanted to avoid it. You might get lucky and try the lost creek wilderness, but is it a little more than an hour away. Or you could hike some of the footholls up by Ft Collins possibly.

Lots of snow still in March. Bring skis or snowshoes. ;)

If you want to hike, Roxborough State Park is nearby and offers some good early Spring hikes.

Interesting Rock formations, cool little hikes, and a nice way to stretch your legs without major altitude considerations.
http://www.parks.state.co.us/parks/roxborough/Pages/RoxboroughStatePark.aspx

A trip I did there in 2010 to scout out a CT alternate start:
Roxboro State Park

If you are willing to drive a bit (less than hour – depending where you are in Denver), the Boulder Open Space and Mountain Park has a LOT of hiking. From gentle strolls at the edge of plains to hiking 8500′ peaks in town.
Boulder OSMP

Some good hiking ideas:
Protrails.com

So, pretty much the foothills for day hikes. But, they are good hikes in their own right!

If you want to backpack, this loop is interesting in a chill, relaxing way:
Twin Owls Loopt

Could be a nice, moderate backpacking trip without too much altitude to worry about.

It is in Rocky Mtn NP, so not too far of a drive.

Naturally, you can car camp at RMNP and do day hikes from the area as well.

If you need some more specific ideas, please ping me!