WHAT? What's wrong with a nice Very Heavy Fighter setup, or a bomber? If your only aim in this game is to fly a battleship, you're best leaving now, they aren't as much fun as you think.
My favorite part of this game was making money to buy a bigger trading vessel, and then making even more money.
Then I started buying fighters, bombers, and using them to pirate people (for fun, and small profit).
I now have two cruisers, but still, I mostly fly my trusty bomber as It's more fun and challenging, at least the poor little trader has a chance!
And yeah, mining NPCs is probably the quickest way, just buy a cheapo 3K ship you don't mind messing the rep up on, fit Charons, and shoot NPC cargo ships, tractor in, sell, repeat, when you get bored (and your rep is totally screwed anyway), pop a Pirate ID on and pirate people too, make em drop 50% of their cargo, and sell it.