Take-out is on "river left" above Ivy Falls. Fairly easy carry and well used. You'll probably see some gas cans stashed by the guides from outfitters on Lac La Croix. Put-in is open and easy too, only slightly steep rise on trail around falls.
Lake after portage: Threemile
Known campsites: not sure
Good current flowing out from below Ivy Falls that quickly leads to wider parts of the river and Threemile Lake.
Portage from Threemile into:
Portage into Quetico Park with QuietJourney.com