Then again, the ConnectUS I see as a position paper to provide guidance. I don't think even Amtrak claims that they will be successful in introducing service on all those routes. What we are discussing here is the set of challenges that is likely to be faced if current practices prevail, on a route that involves essentially running sealed operation through Canada. Of course practices can change and stuff can happen changing those assumptions. Indeed Amtrak adding that possibility to their vision could cause some politicians with enough clout to get excited and do something about it.
I think a more fundamental problem will be convincing the US taxpayers that their funding should be used to run a train essentially bypassing major population centers in the US. I think a NY - Chicago train that runs diverted from Toledo via Detroit and then onto Chicago has a better chance of winning friends, while also avoiding border problems. But that is just me and probably can be ignored as a mad idea. Then again, it came very very close to happening a few years back.
Trains 63/64 ran on the MC across Ontario in the 1970's when 403b meant state funding was only 50%, and NY and MI each contributed their 25%, until one of them cut it off. It was also the first and only Amfleet train run across the Empire Corridor around 1978 with Chicago-based cars cycled off Chicago-Detroit trains. It even had a baggage car. Through the 1970's, only one coach was open through Ontario, the rest of the train sealed. That cut down on Customs time. VIA Rail's Atlantic did so across Maine, but that was until 1994, long before 9/11/01. It would not work today.
All Aboard Ohio had an obsession with running a train between Toledo and Chicago via Michigan, either an extended Pennsylvanian, or diverted Capitol Ltd, or Lake Shore Ltd. I thought it was an awful, poorly thought out idea, lengthening running times by over 3 hours, wrecking connections at Chicago, losing a slot on the NS Chicago Line they would never get back, and making equipment turns in Chicago too tight. But someone at Amtrak was foolish enough to listen to them and sent a 49 that way one day on a test. Luckily CN put the kibosh on it due to issues around Battle Creek, and would have required ICTS locomotives assigned to it anyway.