The alternative is to have small radiation pockets littering the system. Deadly to snubs, harmful to capitals - yet snubs will have an easier time dodging them.
One bigger zone for the visual effect of the radiation pocket (radioactivedust), and inside a smaller zone for the dangerous damage. There are some asteroid props that can be used as landmarks, especially if you add short range light sources with a dim green to them. Keep in mind, though, that there is a limit on how many light sources per system Freelancer can handle. A few of them are no problem. 20+ are tricky, especially when they have multiple objects in range.
