Also, as a side note, with brown water navy, it becomes possible to exploit the massive iron deposits off of Lake Superior. Which at current estimates would be enough iron to keep the entire US fed for over a hundred years. That along with the largest copper deposit in the continental US located just under the tip of Illinois along with significant, zinc, lead, and fluorite deposits in the north of the state(Exploitable with rail lines). To add onto this, the entire state is a massive coal basin, keeping us well supplied in fuel as long as we build enough mines around the area.
Then in terms of oil and boats, there is the Michigan basin, a reasonably large coastal/seaborne oil deposit that's currently not economically viable to exploit, but well, desperate times.
As a funny side note, we would be the only successor state to actually have the local resources to galvanize steel, which would be a critical trade good for building and plumbing.
For a low trade economy running on the equivalent technology of the 1970's, this is basically all of the mineral wealth we could ask for and need for autarky, as long as we can take most of the surrounding lake territory.