I don’t necessarily think there is anything wrong with the 4PL as long as you understand that it’s highly traveled. After my first post, I reconsidered, and realized that what I am looking for in a hike may not be the same as what a group of scouts would want. Of course, if a reservation system goes into effect, that will impact your decision.
I have spent a fair amount of time in the Weminuche (and the South San Juans), but it’s quite a large wilderness, so it’s hard to know where to start talking about it. In general, it’s more rugged and less traveled than the previous option you mentioned, but quite diverse. Chicago Basin from the Animas River is probably the most popular destination, again relatively crowded.
In general, that western part of the wilderness (Needle Range, Grenadiers) has amazing alpine scenery, but it’s not always easy going. Frequent steep ups and downs over rocky terrain, overgrown willows, deadfall, poorly marked/maintained trails, and good campsites can sometimes be hard to find, especially for a large group. It could be frustrating for novices, especially without local knowledge to help choose easier routes.
Farther east in the Weminuche (the CDT is the main thoroughfare), the terrain becomes more moderate and there would be plenty of options for a decent out-and-back, e.g. some pretty accessible lakes with reasonable camping. Â Anyway, I don’t really know the parameters of your hike so I couldn’t make a specific suggestion. But if you have a particular trailhead or route in mind, I’d be happy to give you my thoughts by private message.