Park Ridge is, as its name implies, a long ridge that one must cross when hiking into Mt. Jefferson from the north. There are about 8 peaks along it but one summit that is not far off the Pacific Crest Trail. Awesome views of many peaks in the Mt. Jefferson Wilderness are afforded. There is a vague trail to the summit but the forest is very thin and it's easy to find your way out to it.
It's not that easy to get there. You'll need a vehicle with high clearance and, depending on conditions, 4WD as the "road" to the trailhead is not maintained and very rocky and rutted.
From Portland, take exit 12 off Interstate 205 and head east towards Estacada on Highway 224. Continue past Estacada another 26 miles to the Ripplebrook Ranger Station. Right after Ripplebrook, the road will fork and you want to take it to the right which is now Road 46. Take Road 46 about 27.5 miles from the Ripplebrook Ranger Station further south to Road 4220. This road is just before the huge power lines so if you pass under them or go past an "Entering Mt. Hood Wilderness" sign, you have just passed it.
Turn left onto Road 4220. It does not appear to be signed anymore but know that if you go under the power lines about 50 yards from Road 46, you rare on the right road. It's gravel for a while then turns to dirt and rocks. Drive 6.3 miles to a road on the right. There is a small wooden sign there pointing further down Road 4220 pointing to Breitenbush Campground. Go down this road about 100 yards (this is also where the PCT crosses Road 4220) to a circular parking area with toilets. The trailhead is at this parking lot. If you get to Breitenbush Lake Campground, you've gone too far.
(Note-I know if you are looking at this hike in Sullivan's 100 Hikes in Northwest Oregon that the directions are different. His way takes you a lot longer and, even though the terrible road part of his directions may be a couple miles less than the terrible road part of my directions, I'm not sure it's worth it to use his directions.)