That could make for a cool park. I imagine you'd have clear line of sight between the planets (either by having a clear path between or by raising them up on monuments), and telescopes setup at each planet in such a way that visitors could look at the other planets without people getting in the way.

The Sun would be 1.5 meters across, the Earth would be 1.2 centimeters across, and the whole thing would be 4.5 km from the Sun to Pluto.