In Florianópolis, Brazil, there's a thing called Projeto Helius where someone has placed plaques along the waterfront showing the locations of the planets, to scale. They start off deceptively close together for the inner planets, just a few minutes' walk apart, but then it really takes a while to reach the outer planets.

http://www.1000dias.com/rodrigo/avenida-beira-mar-sistema-so...

I walked as far as Neptune but, like the author of the above blog post, didn't continue on to Pluto. (It isn't depicted on the map, but I just checked and all of these markers are Ingress portals/Pokestops, so it's easy to find other people's maps that show them. Pluto is a little south of the end of the park there.)