Andrew, a decade ago my brother and I got off the train at Flindt Landing after a 24-hr. ride from Union Station in Toronto. We paddled down the Flindt to the Ogoki and down the Ogoki to Whitewater Lake before turning south via McKinley Bay. Once we got to Smoothrock Lake we paddled up the Boiling Sand River for a take-out at Collins. Our route is the one in black and blue on the map included at the bottom of this post. It is about 230 km. long. That is too long a trip for your 10-day solo - unless you are okay with a string of 25-km. days!
Check out the following post for the info -
https://albinger.me/2020/07/15/wabakimi-canoe-trip-from-flindt-landing-to-collins-via-the-flindt-ogoki-palisade-grayson-and-boiling-sand-rivers-intro-logistics-maps/
Since you may not want to cover the daily distances that we tend to, there are options for a shorter route that still starts at Flindt Landing and ends at Collins (on the map it is the route marked in black and is 145 km. ) or at the south end of Little Caribou Lake (the black and red) track and also about 145 km.). Given that you have ten days, one of these two would suit.
Once you get to Wabakimi Lake, you would head down into Lower Wabakimi and Smoothrock Lake before heading south towards the Boiling Sand River and a take-out on the tracks. We paddled right to Collins but you could actually stipulate a spot on the tracks to the east of Collins using the mileage marker found in my posts above.
The other option via Little Caribou Lake does not look any longer. You’d need to arrange a shuttle back to Armstrong where you would wait for the train. Clem Quenville would be a good local guy to arrange this for you. Chateau North is a hotel there where you can splurge for a night while you wait for the train. Going up the Boiling Sands River or the Caribou River will mean a few portages, none very difficult and most pretty obvious. There are a number of trip reports out there that will give you more info on what to expect.
As for the train itself, it seems service has gone downhill since we took it in 2011 and 2012. Since CN owns the tracks, freight always takes precedence over passenger traffic. While we drove up to Armstrong in 2021, the next time we go up tit will probably be by train. Since VIA is a passenger service, there should not be a problem with a canoe in the baggage car. The two previous times we got our tickets in May and the canoe was not an issue.
I will admit that the thing I find most worrisome about the train option is the return date. It is on your ticket so you absolutely have to be there on that day. I have no idea if they would give a paddle a break if you only got there for the next train through two or three days later. The Economy class fare is really a bargain but the tickets are not refundable. I guess it all depend on how sure you are that you will be on that train.
https://www.viarail.ca/en/plan/fare-comparison
Washago sounds like a great place to get on - not as busy as Union Station in Toronto and you can watch as they put the canoe into the baggage car! I was a bit paranoid about that part, worried about the canoe not actually getting on!
Send me an email me at true_north@mac.com if there is something I have put here that needs clarification or if you have any other questions.
The route you are planning makes for an excellent sampler of Wabakimi; it won’t be your last!
Good luck with your planning. It is always good to eliminate as many potential surprises as possible while accepting that new ones will pop up that you didn't expect!