I also did the route this spring, though the levels weren't anything like what they experienced @Beauty of the Backcountry.
After driving partway up Domtar in the spring and then walking the rest (from Saymo), I'm pretty confident that any 4wd vehicle with decent clearance should be able to get at least as far as the forest road past Saymo, where you make a right to head towards Island Lake. Sure, that's not all the way to Gong, but imo, Island and Mystery Lakes are a breeze and somewhat enjoyable (esp compared to Ranger and Saymo). That also sets you up to skip "most" of the Saymo/Island Lake portage.
It might be possible to make it all the way to Gong, but until I hear people start doing it, I won't be the guniea pig to try it

I'm also tempted to head back and complete some more exploration of the area next spring.