The South Summit and the big notch separating yourself from it are clearly visible from the North summit (assuming no clouds - I had cloudy conditions, so I can't give you the view. But I'm pretty sure it's quite nice). In any case, to continue, start descending steeply down the ridgeline towards the notch. It won't be too long before you see the red warning signs and the beginning of a steel wire. The ferrata starts here, and is where you should but your ferrata gear on.
The ferrata descends steeply down into the bottom of the notch - partially over grassy sections, and partially over easy bits of scramble-class rock. It's not very difficult in absolute terms of ferrata difficulty, but it's nice to have the protection. Speaking of protection, the ferrata's wire is a bit damaged in spots, so always be vigiliant and be careful with your hands (and ferrata gloves are recommended).
At the bottom of the notch, you'll see that the footpath splits: one variant goes steeply up a pinnacle that sits directly in the notch, and the other descends and wraps around the tower's base to the right. The pinnacle is a named feature known as "Ninno", and the path going up it has a ferrata cable to allow you to easily climb it. From this western side, Ninno is a steep earthy/grassy climb with almost no rock scrambling required (although it is a bit airy).
To continue around Ninno and on to the south summit, take the footpath that descends around to the right of Ninno. The ferrata wire soon resumes, and there's a fairly exposed horizontal traverse around the base of the pinnacle. After that, the wire ends for a bit and you arrive at a rather ramshackle "camp" of sorts. This spot is known as the Bivacco Valsalvin. There are some ratty open-air bunks and bits of stuff lying around, including some water jugs strategically-placed to catch groundwater runoff.
After the Bivacco, follow indications of trail leading back uphill. You are now starting the steep climb up to Accellica's southern summit. The ferrata wire soon starts again, and on this first part it guides you up very steep grassy slopes. The ferrata wire is anchored on various trees.
Higher up, the wire heads left and out onto the open bare ridgecrest of Accellica Sud. Here the ferrata is much more classic - like the kind of thing you'd experience in the high Dolomites far to the north: an exposed ridgecrest climb over clean solid rock, with solid protection. This section isn't very long, but it's nice. At the top, the route transitions back to a ferrata wire over grass, but in this spot you are still on a narrow ridgecrest with big dropoffs on either side. Somewhat unusual to have grass on a ridgeline that is pure cliff on either side.
If you look up, you'll now see the summit cross atop the southern summit of Accellica, which is only a 100-150 metres away. The ferrata ends, and there are no more technical difficulties after this point.
Clean Steep Ridge Climbing
After visiting the south summit of Accellica, continue along the ridgeline to the south. You are generally going downhill, but a number of small bumps and crests along the way provide a few ups. Generally the crest is out of the trees, giving you great views. A very nice easy and scenic 1+ kilometre of ridgeline hiking ensues.
Grassy Southern Ridgecrest
Again, the skies are trying
This itinerary goes down trail 103A at a place called "Valico Acquafredda" (Coldwater Pass?). This is just another low point on the ridgeline, and isn't really obvious or marked well. You need to look carefully for some trail colors and signage on some tree trunks on the western slopes below ridgecrest. The paint on the trees is somewhat faint, but you can just discern 103A. Refer to my trackmap for a visual. It's easy to miss this spot, and the main 103 trail does continue along the ridgeline (so you'll still be on a trail, just not on the route described here).
Once you've managed to find 103A, though, the going is much easier. 103A is well-marked and the trail itself is well-defined. You'll soon come to another open-air Bivacco, this one without a name I could discern. It is in better shape and less ramshackle than the Bivacco Valsalvin.
Continuing on down along the 103A, things are easy: the trail is obvious and the footing is good. It won't take you long to lose a bunch of altitude.
At the lower end of 103A, the trail lessens in steepness and there are a few lookouts, but in exchange for that you get some less-nice trailbed - it's rather rooty and messy in places.