This out and back from route 11 is pretty enjoyable as long as you aren't looking for scenery all the way. It is very enclosed with trees and there is not a lot to see but it is a steady 3 miles to the top and he path is fairly forgiving. I would not describe this as hard, this is an easy or moderate hike at best. A strong hiker could do this too top to bottom in two hours, if you are little slower 3 hours but that is at a stilling pace. It has two rewarding points, about a mile from the top there is a beautiful vista that looks out over the region and then at the top it has a wonderful 360 viewpoint. Make sure you are going in good weather because if there is low cloud you will not be happy missing the only real reward. I've done this route a few times and would recommend it in good weather.
Started from RT.11 and followed the Bromley Brook Trail up to the ski trail...the last 0.3mi is up the ski slope to the summit. There is no longer a fire tower, but the chairlift ramp makes I nice platform to enjoy lunch, the sun & a satisfying view!
Did a loop with an overnight. Hiked Lyle Brook trail and detoured to the waterfall which was beautiful. Then continues trail which is extremely overgrown with hobble bushes, camped at Bourne pond, woke up and hiked the Branch Pond Trail which is nicely maintained. Stayed on trail to the intersection with AT then turned down service road to Prospect Rock which provides a beautiful view of the mountains to the south and west. Trail continues to the paved road for a mile and a half hike back to start.
Great workout coming in from either side. Coming in from the south, the parking area is just outside of Manchester, easy to get to. It starts out slow, but then gets steep. If hiking in winter / early spring watch out for snowmobilers as that trail crosses this trail, and they can go fast (watch your dogs if not on leash).
The summit of Bromley can be reached from the south at Rt 11/30 or from the north in Peru. From the south the hike is not as steep. The views of Stratton Mountain from the south are terrific. There is an observation tower at the summit allowing 360 degree views. Also a warming hut and a privy.