Couple of safety notes on the Flume Gorge:
1) Some of the low stone walls in front of the visitor's center surround trout pools. They usually freeze up solid, but a little caution is advisable in December and in spring, even if you are following somebody else's tracks.
2) The Gorge itself contains lots of flowing water, obviously. Lots of caution needed if you step off the boardwalk early in the winter (usually you can walk on it starting in January, but you can still find open spots for weeks). From then on, recommended gear in most of the gorge includes not only traction but a helmet. The gorge will be full of ice climbers on a daily basis, and not necessarily very experienced ones. Ice screws, ice axes, and miscellaneous contents of unzipped pockets fall somewhat regularly.