Overshadowed by it's larger and more well known neighbors (Index and Persis) Philadelphia Mtn. is the unassuming lower peak just east of Lake Serene.  Given that the nearby peaks are much more dramitic and that the tree covered summit doesn't offer much of a view, you are unlikely to run into crowds when scrambling Philadelphia.  But, if you're looking to get some elevation gain with pretty good winter trailhead access it's as good as any you'll find.
The group of Everett Mountaineers started out on the Lake Serene Trail and followed it steeply up to the lake outlet, where we crossed to the southeast, climbed through (and sometimes slipped between) huge boulders to gain the ridge east of the lake.  Paralleling the cliffs above the lake, we waded in sometimes waist deep fresh powder to about 3100' and then cut almost due east, tracking Philadelphia's west ridge to the summit.  We retraced our path for the descent.  Avy danger was elevated and the trail does traverse across an open talus slope just below the lake.  Might be a problem with more snow cover or unstable conditions.