We spend 3 or 4 long weekends each winterin the Boat. You'll love it.
Because of the lower elevation, the snow there can get a bit more spring-like in March if there's a warm spell. Typically, count on afternoon highs in the 40s and lows in the single digits. March is a big snow month in the Boat, so if you're there for a whole week, you'll probably get some fresh at least once.
Enjoy the bars and sleep in a bit, because it will be hard in the AM until the sun warms things up.
For an intermediate skier , Steamboat is unparalleled in Colorado....And you'll find plenty to keep yourself occupied.
If you can afford it, it's also fun to stay downtown and catch a bus up to the mountain in the AM. You can walk pretty much all over downtown Steamboat (about 1.5 miles Southwest of the mountain). Of course, you can also catch a bus from the mountain to downtown for your nights out.
IM me if you want some suggestions on food, etc.