Greenlander wrote:
On the plus side, there's no active logging in the area for the foreseeable future. Starting from Ranger (east end of the lake at Lawrence Lake) isn't so bad, and if you don't mind portaging and travel efficiently you can make it to Gong in 1.5 days.
I've done this route twice via Lawrence Lake. I know you specifically say you don't want to access via Ranger/Lawrence, but I wanted to support what Greenlander wrote.
Driving from the GTA and arriving at Lawrence a bit past noon, I was able to get into Island Lake in time for dinner. From there it's only two more portages to Gong. Depending on the time of arrival at Lawrence, someone could get into Gong in a day; in fact, on my way out I left Gong at about 8:00 a.m. one morning, arrived at the landing at Lawrence by around 4:00 p.m. and was back in the GTA much later that night.
You can also extend the portage past Island Lake and go straight into Mystery Lake, then one more short portage to Gong. This would likely be faster overall, but would probably be a bit more total portage length.