There are a lot of such trips in Labrador that you could do. There are
also quite a few trips in Newfoundland, although most are a bit
shorter. The following book might be hard to find, but it has
information about nearly every river paddled in Newfoundland and
Labrador up until the time of its publication. And there are a lot of
rivers in Newfoundland and Labrador...

Canyons, Coves & Coastal Waters: choice canoe and kayak routes of
Newfoundland and Labrador. Dan Murphy, Jim Price and Kevin Redmond.

It was published by Breakwater Press, and is available from the
provincial library -- you may be able to get it on loan.

Andrew