This wherigo cartridge will take you on a "to scale" tour of the solar system from The Octagon to the end of George Street. Zones are reasonably large to accommodate signal difficulties amongst the buildings and should allow you to walk up either side of the street. If you don't feel like the 5-6km space walk you could manage to complete this via space shuttle (car). Both the distances and sizes are to scale. This is frequently not the case in most models due to the sheer relative size of the sun compared to everything else and the large distances involved - in a standard sized text book the planets would be microscopic in size!
A future version of the cartridge may have sound and images - this feature stripped version should accommodate the largest number of players possible.
The cartridge can be downloaded here. Wherigo home page link.
The final geocache is located on a celestial body within the solar system...there is an obvious FTF prize.