Hey robin,
I saw those paddlers too, when I was making sure that the alternate put in was visible on satellite views.
You know GlenL? He was/is quite the pioneer, he's done some legendary routes that no one knows about! (that's a good thing)
He is the inspiration behind my upcoming Cedar River/Rock River trip this spring. He gave me a fantastic sketch map of the Cedar and its surroundings, really helpful.
Parking? Uhmmm, we used to just leave the cars along the road wherever we could fit.
As far as ice out, there was a webcam site:
http://phenocam.sr.unh.edu/webcam/sites/arbutuslake/
that has years of history, photos from every hour, every day, every year going back 10 years or so. It looks at Arbutus Pond, near Newcomb. They (ESF?) are in the process of implementing a second cam on Goodnow Mt. I use the photos, when working, to see ice in, ice out, foliage change, etc.
Statiscally speaking, there is little variation in ice outs, regardless of how harsh or how mild the winter was. Usually within the same week.