On our way to Coonabarabran last week we literally drove past the Solar Systems outer planets (including a dwarf planet).
Said to be the largest virtual Solar System. It sure made the drive interesting.
http://www.solarsystemdrive.com/
The distance between the planets are relative to their size on the billboards, you can't miss them. And it's not just one road to Coonabarabran that has these billboards but several main roads, 5 of them in fact, so it doesn't matter from which direction you're travelling.
Here is a photo I took of Jupiter a few K's out of Coonabarabran.