What's needed are ultrashort, short, and medium range fields.
Ultra short would be java station during the .85 beta period, you mine in a field rite at or within 10k of the a sell point. Much lower profit over time, but good for quick hauls and new players.
Short would be having to travel the length of a system, prehaps just on the other side of a gate.
Medium would be 1-2 system transit distances
And long would be like the penn-NT run, or longer.
Prehaps make all BMM/IMG and other miner faction bases buy ores too, with prices depending on the stations distance from fields.