Parked at Ringwood Manor and followed the Hasenclever Iron Trail west. The trail was rerouted in 2020 around the north side of Hope Mountain through the col between Hope Mountain and Hasenclever Hill. While descending the west side of the col between Hope Mountain and Hasenclever Hill we followed a well defined ATV track which climes the south side of Hasenclever Hill. A heard path off of the ATV track leads to the top of the eastern peak of Hasencvever Hill, which is the summit. On top there is a large boulder and a view looking east towards Blue Lake. We then bushwhacked west along the top of the Hasenclever Hill ridge for ~1/3 mile to reach the west peak. This is where the Black Rock viewpoint is located, which is probably one of the best viewpoints in the NJ Highlands*. The view looks south and the Ramapo Mountains, Windbeam Mountain, the Wyanokies, Long Hill, the Monksville Resevoir, Bearfort Mountain, and Big Beech Mountain can be seen. A well defined woods road (this woods road is not marked on the NYNJTC Map (at least not the 2012 edition)) descends northwest and links with Beech Road in Sterling State Forest. We then followed woods roads to the south of Hasenclever Hills marked on the NYNJTC map to link back up with the Hasenclever Iron Trail and head back to Ringwood Manor. The total trip was around 7 miles I think.
*the Black Rock is technically in NY but the entirety of the view is of NJ.