I'd say those times are pretty realistic if you're floating and not stopping, with minor slowing down with backrowing. Hell, the type of fishing from the boat will change the time dramatically. Dries against the bank is going to take a lot longer (if rowed correctly) than streamer fishing, and particularly nymphing down the middle (gag)
You can easily turn a 6 hour day into a 15 hour day if you're fishing hard and stopping a lot. When I used to guide, I'd almost always be rowing out in the dark from the buffalo jump or the 5k sign.I'd suggest that mac to cars would take a little longer than police to mac, even with essentially the same kms. Lot slower water, and if you have an upstream wind you can be blown back upriver.
Also, if you have your truck down at Carseland for 2 days, be prepped for a phone call from the cops. Better yet, when I did it, my car was registered at my folks house, so my mom got a call from the cops asking if they knew where I was, and were concerned about us. Luckily I had signal! Mel will store your truck at his place overnight if you ask and pay a little more (or used to)