We went up that track in September 2018, south to north, unless your 'Winnie MH is 4WD I wouldn't advise it, there are a couple VERY steep sections, even though they have been concreted they are still slippery and there are a few river crossings, they were only about 300mm deep when we crossed them but if it's been raining up there they could easily get over 600mm+.
I would stick to the 'black top' if I were you, it's a very scenic trip, watch out for cattle on the road closer to Cooktown.

Have a safe trip.

Steel Dog