Actually, no. That old Bunnell Notch Trail section is *really* grown-in these days. After heading up on the Bunnell Notch Trail and cresting the notch, if you know to go straight and plunge into the woods where the KRT turns right, in 50' or so, you *will* see a "The Mt. Cabot Trail is no longer maintained" sign that's identical to the sign where the Mt. Cabot Trail intersects the KRT -- but again, it's all very grown-in.
In fact, the very arrow you requested is now there! Even without the sign there though, RIGHT really is the only obvious direction to go.
How recent is my info? I just dragged in from Cabot an hour ago. I descended the old Bunnell Notch Trail section for about 0.1 mi, then cut N through the woods to rejoin the KRT and consummate today's Cabot mission. I decided I'd take a peak at the section in its entirety (redlining, you know...) once the snow's gone.
BISCUT, if you head up there before the next snow, you can follow my tracks -- but really, the trail and navigation were pretty straightforward. I bare booted the entire hike. The average snow depth is currently 3", with occasional 6-8" drifts. The ground under the snow was still wet and grippy until I hit the switchbacks on the summit "cone," where you need to be careful with your footing - black ice on many of the (slanted, of course) rocks under the snow. I was able to steer clear of it for the most part, and the microspikes stayed in the pack (but do bring them just in case!). I found the hike to be substantially more strenuous than it would be without the snow and ice, because you're never quite sure what you're going to get as you land your foot into the snow -- could be a rock, deep mud, a root, leaves, or a deep slot between two rocks -- which means a ton of extra isometrics for your quads/calves/hamstrings. Once the snow's fully in, things will be easier (except for that 'breaking trail' thing).
Alex