Here is the GPS tracking of the path that my group and I took: https://caltopo.com/m/0N9T
During the hike, I started to recall what he had said about not needing to stick close to Gardiner Creek to go up towards the Upper Gardiner Basin... and following the old map that he had provided was proven useful. I would say that what my friends and I did were more ambitious than anticipated, but it was worth the adventure. Would have loved to spend more time in Gardiner Basin area.
On Day 2, you can see that it was probably our most tiring day. At one point, I found myself knee deep in water after sinking through the vegetation that covered a marsh of some sort. That was scary because I just thought the ground was moist and mushy until my foot broke through after a couple steps. As noted by richlong8, we did not stick close to the creek (or cross it) in the lower elevations since it was all bushwhack and we found some nice (steep) ramps that we could go up and around to avoid any dead ends. Our second night wasn't our intended camping spot, but it was necessary as a lot of the members in the group were exhausted by evening time. It took us about 11.5 hrs to do 10.5 miles as a group. We found some okay camping spots that weren't too flat, but at least they were durable rocks.
You can see on Day 3, we tried going on the northern side of the Gardiner Lake at 11,407', but had to turn around. This was due to a steep snowfield crossing that the majority of the group (including me) did not feel comfortable crossing. This was an additional 1 hour detour as we were able to compare time with two of the group members decided to go high up on the snowfield to cross it because they did not want to backtrack. Quite risky in my opinion.
I also recall there was another trip report in regards to coming down from 60 Lakes Col. to 60 Lakes Basin area about a sketchy traverse where the ledge is only a foot wide or so. I found that part to not be too bad and was shorter than expected. It was actually an exciting spot for me because it added a unique experience to the hiking. You can catch a glimpse of that crossing in my video later in the post.
Overall, the off-trail section was very rewarding, and I would love to go back to it next time and spend more nights there. I love the solitude we had for two whole days.
I created a video for it too if you would like to see, although that may spoil some of the excitement of exploring the area yourself. I uploaded it here:
The person you see the most complaining in the video is my wife. And I will have to say that despite her complaints, she said she enjoyed it overall, but probably prefer to stay on trail.
If you have any questions, I am happy to answer!