I think Red Cone to Radical Hill to Middle Fork Swan River to SOB Hill, to Georgia Pass and back down to Jefferson would be a decent loop. Would prefer early morning as its a series of trails that will get very busy on the weekend being close to the front range. Also, a bit of rain in the forecast. The weather can turn quickly
I am actually going to pass on this one--12 is too late of a start for me. Enjoy it though, its a great trail and you'll have some awesome views. Take it slow on the downhill side, lots of loose rock.