If you scroll to the end, out beyond Pluto, it says, "Might as well stop now. We'll need to scroll through 6,771 more maps like this before we see anything else."
For those curious, after scrolling 6,771 more maps, that is approximately where you would expect to find Proxima Centauri.
However, there are actually some other points of interest along the way (between Pluto and Proxima Centauri), including Eris, 90377 Sedna and Voyager 1, to name a (non-exhaustive) few.
If we redid it with the solar system (diamater: 10bn km) as a single pixel then it would be 3,800 pixels to Proxima Centauri, 94m pixels to cross our galaxy and 2bn pixels to get to Andromeda, the nearest "major" galaxy at 2m light years away.
One of the snippets mentioned Sun->Pluto was around 665~ widths, I believe; does this mean the distance from Pluto to Proxima is 10x the width of our planetary system?
If so, that is much closer than I thought. I had always held the notion that the nearest solar system was magnitudes greater distance than our own planets (although I admit the distance to pluto from here is pretty damn enormous relative to the distance to other planets in our system).
If moon = 1 px is your yardstick, then I can see not putting Voyager up there, but otherwise I'm with you. If you stick Pluto in at about 2/3 the size of the moon, no reason not to include Eris (about the same size as Pluto) and the half dozen or so other TNOs that are a half or more the size of Pluto.
For those curious, after scrolling 6,771 more maps, that is approximately where you would expect to find Proxima Centauri.
However, there are actually some other points of interest along the way (between Pluto and Proxima Centauri), including Eris, 90377 Sedna and Voyager 1, to name a (non-exhaustive) few.