DavidjohnDavidJuniorEastcoaster,
me and my little bro did your trip last year as a day hike (Putvin Trail/Mt. Stone Summit/Scout Lake/Upper Lena/Lower Lena/out). Hardest part for us was decending after summiting Mt. Stone, probably because we just went straight down from the summit to the little lake just to the east (you continue north from there to Scout Lake). If you go to the summit, you'll see how stupid this was, but then we were looking for adventure.
2nd hardest part was finding the trail from that little lake up to the ridge to the east of the Mt. Stone summit, which you follow for a while before dropping down to Upper Lena Lake. We lost the trail twice, as it gets faint in some places. But it was Class 2 all the way, including summiting Mt. Stone (but not the route we took down from the summit). If you don't agree, then I've got some Class 3 that you'll think is Class 5 for ya. I don't think snow will be a problem for you, but bring an axe just to be safe and look cool. We didn't and were fine. I really don't think you'll need a helmet, but my lawyer advises you to bring one and wear it at all times. Be sure to put a sticker on front that says "Trask".