My wife and I drove our Prius to the locked gate 3 miles from the highway with bikes on the back. Check the fine print on the sign at the gate. It notes that the area is closed to all access from August 1-Dec 31st except by permit.

We rode our bikes 3.5 from the gate to the upper trail access. We had to dismount and push our bikes up the final half mile of road because it was too steep to ride with our heavy packs full of water for the day. We probably should have just ridden to the lower TH to save our energy. It was going to be pretty hot and there's no water on the trail. It took a minute to spot the upper trail access as it isn't marked.  GPS helped.

From the upper trail access the trail is in pretty good shape all the way to the summit. It was a little overgrown in a few spots, but good. Bear grass and rhodies were dried up and crispy on most of the trail, but were still blooming on the open slopes during the final mile to the top. Views were great! More wildflowers up here, too. Bugs weren't great on the way up, but the summit was the worst. We stopped for a break below the summit to try get away from the mosquito swarm. I killed 30 of them but eventually stopped counting. They seemed to chase us all the way back to the bikes. The ride back down was fun with great views over the water. We saw no other people.

We parked at the Rayonier gate and hiked on the road from there. From the signs, it looks open until August 1st without a 'hunting' permit. On our way out, someone with gate access was coming out and was very friendly and not surprised we were hiking on the logging roads. It was on a Saturday, so might be more dangerous if there was loggers working on a weekday. 

It is quite a hike from the gate to the actual trailhead, but spectacular views start right away. The logging area itself is not very scenic, but there are great views of hood canal. 

After reaching the trailhead, there is a trail in decent condition for a few miles, but eventually you end up back on a logging service road until you enter a VERY overgrown 'trail' to keep moving west on the ridge line towards Mt Jupiter's peak. It is not an easy trail. Expect to go half or even slower of your normal hiking pace because there is a ton of bushwhacking to do. There are some pink ribbons keeping you on track, but they are sometimes hard to find. It is easy to get off track so a GIS/GPS map is required. We didn't make it to the peak. We hiked 10 miles round trip and didn't even make it onto the edge of the avenza map. Definitely start very early in the morning if you want a chance of making it to the peak.

 (Partial report, I turned around about 8 miles in)  
I parked at the closed Rayonier gate and bicycled up the road (well, pushed a bike up some of the steeper sections). I skipped the lower trailhead since I read several reports of it being very overgrown and difficult to follow and instead started from the upper trailhead where it intersects the logging road  before the radio tower (N47.69131° W122.96697°). The trail crossing the burned / logged area was in surprisingly good condition and hasn't eroded much. It looks like only the logging slash burned, and the surrounding woods didn't catch. The trail through the woods is in very decent condition with only a few easy to bypass blowdowns. I encountered snow around 3200' and slogged up to the saddle around 4000' before I decided I was moving too slowly (and the post holing was miserable) and turned around. Total one way distance (including road) I covered was 8 miles and about 3600ft gain. The trail past this point was under so much snow that I couldn't tell the condition but if it's anything like the first part it was in good condition for the access issue. Riding my bike back down the forest road was a blast (if a bit scary in some places). I think it's worth lugging a bike up just for how much time you save on the way down.

I write this trip report because there seems inconclusive information on the status of the trail.

There were reports of car vandalism at the gate to the Rayonier owned area. I decided that I did not want to take such a risk and parked the car at 101. There is a large parking lot right at the start of Mount Jupiter road.

I biked the first 6 miles / 3000 ft to the junction of the road to the radio tower. The gate at mile 3 is closed and there are lots of warnings about private property and ongoing logging operations. There was logging equipment but I did not see any logging operation in process.

I joined the hiking trail just 100 yards (at 3000 feet level) in from the junction to the radio tower. The trail there is newly constructed through a burn/logging area for about 1/4 miles. I pushed my bike past that area and stowed it away in the woods on public property. There was nobody else around anyway.

I took me 1 hour 45 minutes to bike to the junction starting at 7:45 AM. It is very steep and  I needed a 30/50 set-up. It still pushed me to max heart rate.

I could not see the hiking trail coming from below through the burn area. So I do not know the status of that lower trail. The Forest Service on their web site states that the trail is open (unlike the WTA web site). See comment below by rkjenner.

The hiking trail itself is in perfect condition. The growth at times does not reach higher than the knee and it is really no problem. I reached the peak at 12:15 PM in four and half hours.

On the way down, on my bike, I saw some people working next to a truck (in the private area). They waved, greeted and were friendly.

I do not understand how the arrangement with Rayonier works. The trail is not accessible other than through the Rayonier private area. They distinctly forbid using it without permission. On their web site they say they grant permission if you buy a $300 hunting license. I certainly would not pay that money and I did not call to ask for a permission. 

My assumption is that there is no problem, especially if you go on the weekend when no logging is in process. Otherwise you just need to be lucky.

I do not know about the vigilante that took it upon itself to flatten tires. I think the best bet is to just bike up form 101. But it requires quite some effort.

Drove out to see what's up and found the road closed. After reading stories about punctured tires, didn't want to mess with it.