You can also check Jeff Smoot's site. He has a page deidcated to easy summit hikes and scrambles:
http://climbingwashington.com/features/summithikes.htm
I highly recommend the hike to Hannegan pass/peak- the views are amazing: Mts. Baker, Shuksan, Ruth and a peek into the Northern Picket Range. All on good trails with the majority of the elevation gain right at the end.
It you bring along ice axes, the climb up Mt. Ruth is also supposed to be a nice outing, though exposed in places.