Yes.
Montreal would be the busiest port in North America, followed by New Orleans.
I suspect that the route of the Erie Canal was decided for military reasons .... to prevent Brits from interfering with trade between the Hudson River (New York City at the mouth) and the Great Lakes.
Little impetus to dig an Erie Canal when you can go straight North along Lake Champlain, the Richelieu River to the St. Lawrence River and upstream to the Great Lakes. The canal at Chambly is much shorter and merely by-passes Rapids and a portage along a historic canoe route.
WI the border between Quebec and New Hampshire (almost 45th parallel) was continued all the way across the prairies and Rocky Mountains?
The new border would reach the Pacific Ocean just South of the mouth of the Columbia River ..... territory that the Hudson Bay Company had a loose claim on.
Next question: would Britain gain most of the Williamette Valley?
WI the border continued east along the 45th parallel?
This would allow Canadian railroads - and later the Trans-Canada Highway - to run straight from Montreal to southern New Brunswick. Since most Mainics live along the coast, losing the northern 2/3 of the state would be a small loss. To this day, northern Maine is sparsely-populated with few roads.
The Great Lakes a complex region to draw a border through. Negotiations at Ghent (post-War of 1812) requested canoe access to the headwaters of the Mississppi River through Lake Itasca. More forward-looking negotiators would have requested access (Great Lakes to Mississippi) via the south end of Lake Michigan (site of the Chicago Sanitary and Shipping Canal).
The Grenville Line (proposed at Ghent) included massive reserves for Britain's native allies in Ohio and other Mid-Western States. Would the USA have agreed?
How many of those Americans settled in the Ohio River Valley have been willing to become "late Loyalists" in return for land grants?
OTL The current prairie border was drawn at the 49th parallel to allow British settlers access to the mouth of the Frazer River. To this day, Canada only has 4 ports on the Pacific Ocean: Vancouver, Squamish, Kitimat and Prince Rupert.