I did this trip last year in 2 1/2 days. We hiked over Shepherd's Pass and camped near the second lake to the south just over the pass. I'd recommend this spot as it's a great staging point for Mt. Tyndall and you don't have to carry a full pack in to and out of the Williamson Bowl. Day 2 we did Williamson and Tyndall and hiked down to the Pothole. We hiked out on the morning of day 3.

Check out his webpage. There is no defined route but I found it easy navigate based on the pics and route description on this site.

https://www.scaruffi.com/travel/williams.html

Good luck! It's an awesome trip.