Telluride's City campground is not free, but it is super nice, quiet, and in town. Would you pay a little money to walk from your tent all over town? https://www.telluride-co.gov/181/Campground
Just outside Silverton, FS 585 to the South Mineral Campground, along the road,before the FS campground has lots of camping spots. If you stay on 585 after the campground, the scenery gets fantastic and there are spots, with fewer people, but the road gets increasingly rough. Some the spots are pullouts, others are pullover and carry your gear 50-100 yards to the spot on the river.
All this is solid , because i was there this past June.