type-B wrote:

Question for the locals: is the bike course suitable for a group to come up and do a pre-ride this August? I saw in a post earlier that certain sections are even closed to cars on weekends, is that right? This assumes we’re not a-holes and ride single file, etc.

Yes, a good chunk of the course is closed to cars on Sundays up until either 4 or 8pm, depending on the road. There's a section in the middle where you'll need to take the Multi-Use Path (MUP) along the river/canal to get between the parkways, but most of the kms of the course are closed to traffic. The exception is Col By parkway on the east side of the canal, and the parts downtown. If you take the MUPs as a go between, I believe that you can do the route without traffic (though its been a while since I've done the Rockliffe part so someone please correct me if I'm wrong).

The only catch is that the parkways are generally well used by families and non-athletes out for a Sunday ride. The stronger cyclists tend to move to the much more hillier Gatineau side. I tend feel awkward blasting through at any kind of speed if its busy. I wouldn't do it at race pace, but if you're looking to recon the course and you're courteous to those also using the parkway, then its good to get in a course recon.

If you really want to scope out Col By, there's a MUP parallel to the route - but this might be better as a run recon (it's on the run route too) - it can also get busy with lots of walkers and runners.

More info: https://ncc-ccn.gc.ca/events/weekend-bikedays

ETA: One thing I should note is that the route marked as "Sir John A MacDonald Parkway" in the Ironman route is the same thing as the Kichi Zibi Mikan in the NCC site. Ironman is just using the old name.