Here’s a map from erstwhile rail and transit blogger, Alon Levy, with a proposed “high-speed” / low-speed rail network that would connect to Minnesota.
First, the map itself:

Red denotes high-speed lines, with a top speed in the 300-360 km/h range, not including the occasional enforced slow zone. The average speed would be 300 km/h in the Midwest, where flat expanses and generous rail rights-of-way into the major cities should allow the same average speeds achieved in China. … Blue denotes legacy lines that are notable for the network, including all lines that I believe should get through-service to high-speed lines; but note that some lines, like Minneapolis-Duluth … do not have through-service.
For Levy’s proposal, the Chicago-to-Minneapolis travel time would be 2 hours and 30 minutes. There would also be connection north to Duluth. Here’s what Levy writes about the route and frequency patterns, where the route skips the current Amtrak route along the Mississippi River, and stops instead in Rochester:
On most lines, multiple stopping patterns are unlikely to be worth it. The frequency wouldn’t be high in the first place; moreover, the specific stations that are likely candidates for local stops are small and medium-size cities with mostly short-range travel demand, so serving them on a train stopping less than hourly is probably not going to lead to high ridership. Among the lines coming out of Chicago, the only one where I’m comfortable prescribing multiple stopping patterns is the one headed east toward Cleveland and Detroit.
The conclusion:
The likely impact of HSR on the US is different, because the country is too big for a single city’s network. However, the Midwest is likely to become a more tightly integrated network focused on Chicago, Texas and Florida are likely to have tighter interconnections between their respective major cities, and the links between the Piedmont South and the Northeast are likely to thicken. HSR cannot supplant air travel at long distances, but it can still create stronger travel volumes within its service range, such that overall trip numbers will be much higher than those of air travel, reducing the latter’s relative importance.
This would be amazing, but the US hasn’t meaningfully invested in passenger rail in almost a century, so I am not holding my breath here.