Chris Pluchar
Google
Boundary Peak is a real challenge for most, I can confirm that after we completed it yesterday. For reference, if you've done Mount Borah, I'd say it's not as difficult as that. The altitude can get you on this one if you're not accustomed to hikes of this sort or live at low elevation with little time to adjust.
We took Route 6 to Queen Canyon Road and took that to the Queen Mine Trailhead. You 100% need an SUV with 4 wheel drive if you're want to park at the trailhead. There are many rough spots on the road, the worst of which is about 0.8 miles from the trailhead. So if you don't have 4WD, that's as far as you'll be able to go, which will add about 1.6 miles to your hike RT.
One reviewer mentioned snow and ice in the last 500', but we only saw some very small patches of snow. No snowshoes or crampons were required for this one.
Temperatures were cool, but comfortably so. I did most of it in a t-shirt and light hiking pants, only adding a hoodie at the top when we were taking in the views and snacking.
Navigation was mostly straightforward, though as you approach the final miles of the ascent, I'd suggest hugging the ridgeline for some scrambling over boulders as opposed to dealing with any scree on the sides. There are plentiful hand and footholds for scrambling with nothing ever feeling unsafe.
On the descent, the trail disappeared on us in the section before you reach the large rock by the Trail Canyon Saddle. I wasn't checking All trails often enough and we veered off into one of the very large and very loose scree fields. Once we realized it, we were able to take a hard 90 to get back on track.
Beautiful views at the top, plenty of notebooks to sign your name in, and a harmonica if you dare. You'll likely also have cell service at this point. We were joined by the one other person hiking it yesterday, he had come up via the Trail Canyon route and said he was able to park at the trailhead, though I'd look for his review to confirm.
If you're young and experienced, you can get by without walking sticks, but I'd recommend them, especially for the descent.
I drank about 3.5 liters of water in all.
Good luck!