Bearpen and Vly have the distinction of being the only two 3500 peaks that are outside the "blue line" that bounds the park. Often done together, the two are technically not trailed peaks, but no one could possibly call them bushwhacks.
I hiked them with another aspirant. If you want to do both peaks together, start from Halcott Mountain Road (route 3) to either the north or south - it is unpaved in the middle and not suitable for ordinary cars. We chose to approach from the south, and the hardest part of the hike was finding the trailhead: Route 3 is not consistently marked and signed.
Once we finally found the trailhead, we parked and headed up Halcott Mountain Road to the junction shown above. To the left is the snowmobile trail that leads to Bearpen. To the right is the road. Perhaps 25 feet down the road is a trail off to the right that leads to Vly.
We went up to Vly first. A canistered peak, it doesn't have any real views. At some spots, you can turn around and see Bearpen behind you through the trees. Even though the trail is unofficial, it is marked with blue paint blazes. It's steep but otherwise unremarkable.
After Vly, we headed up to Bearpen. All the way up the roads and snowmobile trails, we saw a great number of toads, which was fun. The snowmobile trail was unsurprisingly easy to follow. Now, that said, we wanted to take a shortcut we'd heard about that cut some time off, but we couldn't figure out which side trail it was. (I was told afterwards it's the one with the "DANGER" sign at the lower end.) But if you stick to the snowmobile trail, you can't get lost.
Bearpen had a brief life as a ski hill, and at the top you can see the remains of the lift as well as some other old equipment, including a car. There is a nice view at what I presume was the top of the run.
I don't think I'd seriously consider any of the other approaches unless I was doing something like the grid and needed variety (and that's not going to happen). Coming from the north adds substantially more elevation gain, and the other approaches don't allow you to easily do both.