Congrats on finishing the timeline. It was a wild ride following this one.
I keep hearing people talk about SV, but I've never checked it out. Might do so in the future.
If I had to guess, they likely just Googled a map of New Sweden and they grabbed the first thing they saw. It happens all of the time on Geography Now. There are a lot of videos of theirs where alternate history maps pop up.
No joke my first thought when I saw this photo (and before I read the text) was that this was a plan to create a new state after rising sea levels swamped the east coast.