Let me try again. How often do your games involve traveling to/adventuring on non-mainworlds in a star system?
When I use expanded gen...
Let's see... using the EC mentioned above...
New Wisconsin system: Both Racine and Eau Claire have been visited by PC's.
Kamaj system: Both Kamaj and the asteroid belt were potentials, but only Kamaj made it into play
Doylee system: They went to Coatl, Axotl, Xoctomil, and Mixotl. And did so largely by N-space, tho' they jumped the 7 AU from Quetzal to Coatl.
Aurora System: Hail belt and Aurora I. They were investigating a rumor about Aurora I, and n-spaced to the belt (≤0.5 AU)
Ryokan: Only one inhabited body.
Note that I did tweak the pop gen mechanics slightly - sufficiently so that the results are distinct.