The existence of the Virginia Plan (the Large State Plan) and the New Jersey Plan (the Small State Plan) indicates that balancing the differing interests of high- and low- population states was a prominent concern of the founders. I think they would expect states to often align by population size since that very thing occurring at the convention led to the compromise written into the Constitution.
https://en.wikipedia.org/wiki/Virginia_Plan https://en.wikipedia.org/wiki/New_Jersey_Plan
I have a hard time conceiving of matters that states would separate themselves on by population size other then proportional representation in Congress back then.
I suppose, however, that the majority of low-population states were also frontier states, seems like a fairly compelling distinction.
>I suppose, however, that the majority of low-population states were also frontier states, seems like a fairly compelling distinction.
Not so much, unless you consider Massachusetts, New Jersey, Rhode Island, New Hampshire and Vermont to be "frontier" states in 1787. Actual frontier states like Georgia were in favor of the Virginia Plan as they figured their population would grow soon enough and they could take advantage of their eventual large population (with slaves being counted as 3/5 of a person) in a "Virginia Plan" world.
The Connecticut Compromise[0][3] ended up in the Constitution as a reconciliation of the Virginia Plan[1][4] and the New Jersey Plan[2][5], with the larger states supporting the Virginia Plan and smaller states supported the New Jersey Plan.
The above is incredibly abridged and ignores much context. As such, I strongly recommend you read Article I, Sections 2 and 3 of the US Constitution[7] (the result of the Connecticut Compromise) as well as the original Virginia and New Jersey plans, or at least the wikipedia pages I linked for a much better discourse on the topic.
[0]https://en.wikipedia.org/wiki/Connecticut_Compromise
[1] https://en.wikipedia.org/wiki/Virginia_Plan
[2] https://en.wikipedia.org/wiki/New_Jersey_Plan
[3] The current system. Which differs from the original only in direct election of Senators, rather than them being appointed by state legislatures[6].
[4] Proposed a bicameral legislature with both houses apportioned by population.
[5] Proposed a unicameral legislature with one vote per state.
[6] https://en.wikipedia.org/wiki/Seventeenth_Amendment_to_the_U...
[7] https://constitution.congress.gov/constitution/
Edit: Added the missing link.