This isn't meant to single anyone out. It's a common mistake -- one I'll admit I made a few times back when I was newer and over-excited about my first couloir season. But it might be best to avoid giving advice on routes you haven't personally done.
I want to reiterate Kelso Ridge. It was my first Class 3, and I returned a second time to take my friend and girlfriend up their first Class 3. It's sustained but also has tons of good spots for a break. The route-finding is easy. The rock is mostly solid. The challenge and exposure are there, but neither are overwhelming. And the descent off Torreys is a breeze.
I can't speak to the Sawtooth because I haven't done it. I do have experience with the willows, and they're as bad as everyone says.
Wetterhorn is another good option if you happen to be in the San Juans. I know it's listed as a "Very Difficult" peak, but I found Crestone Needle to be pure Class 3 bliss. I suppose I'd more recommend it as a second Class 3 because it does require a ton of scrambling. Longs Keyhole is all right I guess, but I didn't find it as fun or sustained as these other routes.
“There are two kinds of climbers: those who climb because their heart sings when they’re in the mountains, and all the rest.” - Alex Lowe
"There have been joys too great to describe in words, and there have been griefs upon which I cannot dare to dwell; and with those in mind I say, 'Climb if you will, but remember that courage and strength are nought without prudence, and that a momentary negligence may destroy the happiness of a lifetime. Do nothing in haste, look well to each step, and from the beginning think what may be the end.'" - Edward Whymper