That trail you took to climb out of Look Park I used to take, going the other way, as part of a 10.5 running loop from my house. As I remember it, it is not anything I would consider riding a bike on.
I don't think I've ever ridden on the bike path north of Audubon Rd. I knew it just ended somewhere near the Williamsburg town line. My routes that use a stretch of the bike path (what we did last summer) turns south off Audobon Rd. (as you did coming home).
Ah, that makes sense (re Audubon Road). The part north of Audubon has a couple of hundred yards that are dirt/gravel, perfectly OK but I hadn't remembered any such surface when I'd ridden with you.
And the little path right above the river -- main thing I was worried about was ice, but none to be seen.
A long time ago I thought about making an O map of Look Park, but that's all I did, think about it.