Super fun loop! Went clockwise as others have suggested - and I agree, this is probably the best way (Cub lake first, Fern last). Bear Lake seems a little out of place since you have to do an out and back to get to it but oh well. Otherwise the rest of the loop is so beautiful and crosses through so much varying terrain. I ran this on July 1st and there was still snow starting from just below the Banana Bowls under Flattop mountain all the way to Lake Helene and down to Odessa Lake. The trail from Helene to Odessa is half under water or snow so some bushwhacking/ navigating is required here- with the snow this can be a bit dangerous so I would recommend waiting till even later in the year when the snow is melted more to get a faster time. I didn't do the loop around Bear lake to try and shorten the route while still meeting the criteria. I also found a slightly faster route around Bierstadt Lake. I'm sure there's a few other places where small cuts to the milage can still be made.
4h 23m 3s