The Wenonah Northfork was actually a rotomolded polyethylene hull. I believe it was Wenonah’s first entry into rotomolded poly hulls. And perhaps their last as it was not produced for long.
G/flex epoxy will adhere to polyethylene is you prep the hull properly.
http://www.westsystem.com/ss/g-flex-epoxy-adhesion-data/
I’m not sure what you mean by “smooth things up a bit”. If the hull has scrapes and scratches I’d just leave them alone unless they are especially deep. Trying to resurface an entire poly hull bottom would be a PITA, and the Northfork already weighs close to 90 lbs.
The Northfork needed some arch in the bottom; the long flat bottom tended to develop permanent concavities and oil canned when paddling. If that’s what you mean by “smooth things out” you could try adding some vertical stand-offs from the yoke and seats to the bottom.