If it's your first time, I would recommend going to RW (Lot C) instead of Skyline. The Skyline trail going up to RW is something hard to find and it's very raw. The RW trails are more groomed. Plenty of rocks at both though.
Fyi, Skyline is not really a part of RW, it's Ramapo Mountain. You can connect Ramapo Mtn and RW via the Yellow Trail and Cannonball Trail from Skyline. Skyline is also not really a name or a trail or anything .. people just call it Skyline because the parking lot is on Skyline Drive .. it's really Ramapo Mountain.
I'm not really sure where you want to go .. RW or Skyline?