The challenge is to have a rogue Kerbin which only has a small time window to get in to the inner system. Your goal is to either:
Colonize a planet successfully and be self-sufficient(extra planetary launchpads mod and drills)
Create multiple self-sufficient stations(see above possible mod)
or
Get to the top of the tech tree so you can 'redirect' Kerbin into the system (hyper edit)
So that's my take! Thanks!
-Noah