(The picture to the left and below has been hyperlinked to the NCC Sunday Bikedays for more info.)
In Gatineau Park, there is ample parking at various lots, you may also want to familiarize yourself with a parking lot prior to departure as it will make your route selection easier once you arrive at the park. (Click the picture for more Gatineau Park bikeday info.)
From experience, you can section your bike riding (as example) with existing bike paths on the Ottawa side to extend your riding past the length of the parkway closures. Also, trying to tackle all of the closed parkways in one day is a big feat and is more enjoyable to complete on separate occasions.