Summary - the hike to 3977 (from copper creek) is relentlessly steep, easy to follow and ends in a summit with great views. The route on FR 41 from the Sunset Falls campground is festooned with holes and washouts, some of which are spectacularly large. Be prepared for the hike, which rises 2500 feet over 2.6 miles; the first half is harder than the second but both have very steep sections. You can do this activation with just an HT; ND7Y and I each made nine 2M QSOs within twenty minutes of arriving in the AZ. The peak is small and rocky, bring a mast along if you want to work HF from the summit. Otherwise you can go a bit below to find trees.
The Long Story - The trailhead for 3977 (discriminator peak) is in the Copper Creek canyon and can be reached by taking FR41 out of the Sunset Falls campground. 41 is never terribly steep or narrow, which it makes up for by being littered with huge potholes and washout. While you might navigate your way through in a Prius, I'd suggest something with higher clearance and 4WD. Here's a GPX file of the routes:
The road from FR41 down to the trailhead is steep and narrow but no worse than anything else you've driven to get this far. You can park here or at the small campsite a bit further on, next to Copper Creek. Cross the bridge and start a gentle climb to the first fork, then head right. The trail, which generally goes straight up the fall line through the forest, is easy to follow. It is also, in places, relentlessly steep. Halfway through you get a break before you start climbing again. There is one more plateau before you ascend the last few hundred feet to the summit. As you'll see if you look at a topo, the route follows a narrow ridge. I planned for two hours of hiking; we managed it in about an hour, forty minutes, with stops.
And that's the view... Mt St Helens, Mt Hood, Silver Star, Lookout and other local peaks are easy to see from here. The peak itself is rocky and without trees. You can put up a mast or go down a bit to find trees if you want to put up a wire. Tyler ND7Y and I had no trouble making 2M contacts with an HT and halfwave whip, nabbing nine each within thirty minutes of reaching the summit. Even with my poor antenna setup - a EFRW about nine feet above the ground at the far end, I made CW contacts on 40 and 20 meters. ATT cellular data signal worked well, as did APRS, so spotting and messaging is easy.
3977 is definitely worth the hike. Great views, easy 2M contacts, and a nice place to hang out a couple of hours if you want to work HF.