Liberty–Flume Loop Professional Review and Guide
"This is an epic day hike beginning with a gentle forest walk leading to a hand-over-foot scramble up steep ledges, then a spectacular traverse over two 4,000-footers. The loop up the Flume Slide Trail to the top of Mount Flume, across the southern part of the Franconia Ridge to Mount Liberty, and then down the Liberty Spring Trail/Appalachian Trail (AT) is as rewarding as it is challenging. The rewards come from the views atop these two 4,000-footers and the accomplishment of completing this demanding route. The challenge comes from the climb up the Flume Slide Trail, which has a couple of rather smooth and vertical rock walls to negotiate.
This hike is definitely for experienced hikers who have basic rock climbing skills, though this is not a technical rock climb per se. It is also a high-mileage day with over 3,000 feet of vertical gain, so it’s not for the weak of leg or lung. On this loop, plan to hike up the Flume Slide Trail as it is described here, and only if conditions are dry. If you are unsure of your ability level, consider hiking up and down the Liberty Spring Trail."