askchapo

• You'd have access to the New York harbor (and the whole Hudson) as well as the Erie canal. The northeast basically sits on the largest modern trade route for the midwest and Canada.
• You'd probably annex Pennsylvania as a buffer state
• Due to NE train infrastructure you can take DC as a large fortification and resupply. At this point you control the vast majority of Atlantic infrastructure.
• Large population to draw from.
• Invasions from the South and West stymied by the Appalachians and Great Lakes.

That said, Grand Chicago Trade Union is the biggest wildcard. You control one of their access to the Atlantic via the Erie Canal and Hudson, so you two will be hot and heavy diplomatically over access and costs. They are also very wealthy in goods, control vast sparsely populated territory, and their Trade-Electors are highly independent. Mitigating factor is they are constantly at war with the neo-confederate warlords along the Mississippi as well as rivals with the Republic of Texas following the collapse of the Louisiana Territories.