This route is known as Blades Couloir by the Alpinbock boys cause there are rocks that stick up under the snow like blades that can rip a new asshole.
Once in the couloir follow it to the top and the notch. If has pretty consistent grade. Surmounting the north summit of Mt. Olympus is easy 5th class.
From the North summit one can retrace their steps and descend the couloir.
Though many folks ski Blades, bum sliding it a lot of fun. If you catch it in the right condition it is possible to slide from the notch down to the waterfall in one go. By pass the water fall on east side (skier's right) and continue for a bit more before walking out to Neff's Canyon.
NOTE: If bum sliding be aware that it has a secondary angle that pushes you into the west side of the couloir. This also happens to the side that catches sun. As such, a moat will form that can be extremely dangerous if you go into it. It has caught more than one experienced bum slider.
Take the Neff's Canyon Trail until it levels out and goes from a road to trail. At this point the creek has a left (main) and right fork. Cross the creek at this point and follow the old pipeline road as it goes along the right (west) fork of the creek. Eventually the trail leaves the creek meanders through the woods. If one stays in basin formed by the creek meandering over the many year the trail ends up at a waterfall. By pass the waterfall on the east side (climber's left). At this point you are in Blades Couloir.
Ice Axe and maybe crampons.