Some nice snowshoeing east of the divide is the Brainard Lake area. It can be busy, but if you do it during the week, itis not too bad. Very beautiful, not too hard with plenty of options.
Pick up TRAILS ILLUSTRATED MAP# 102 INDIAN PEAKS/GOLD HILL. Long Lake is a good one to snowshoe to. Brainard is about 45 minutes or so away from Boulder.
Another option is Rocky Mountain National Park. About 1 hrs drive. One of my favorite places to snowshoe, with a good “view to effort” ratio is Mills Lake. It is 5 miles R/T.
http://www.thespiritoftherockies.net/spirit/Hikes/MillsLake/MillsLake.html
You would get TRAILS ILLUSTRATED MAP #200 - ROCKY MOUNTAIN NATIONAL PARK.
Since you are coming to altitude, take it slow. I gave you some suggestions that are fairly easy. The grade of these hikes are such there are no avalanche dangers.
Boulder has many places where you can rent snowshoes for about $8-$10 a day. You will be able to pick up the maps $10 ea.) easily as well.
If you have other questions, e-mail me. more than happy to answer them.
Mags