I lived out in that space for a good while (before and after launch, I'm only now coming in from the cold so to speak). It's all I knew. I'm coming in now to find conflict zones. If a system has a color on the map it likely has a station (I think it always does actually). Independent means they are independent. HOWEVER they can have an allegiance to Federation or Alliance. Often I'd find many allied with Federation where I was because everything was either a blue or green dot where I was.
Yes you can find many unsanctioned outposts. These do NOT perform ship scans. You are free to dock here with illegal cargo. They are easy to visually spot as well because they have red skull holograms on the station (usually platforms).
Many times you can refuel and repair and then sometimes rearm (as I recall prices weren't as nice). Less frequently (though you'll find it enough) you can find outfitting and even more rare a shipyard. You will need to go back to Federation, Alliance, or Empire space to get more items, ships, etc.
The systems on the edge make for a great place to refuel and return to in order to sell exploration data. You can practically pick any direction and head out and loop back another way and sell tons of exploration data.
The gray dots are of course empty. No stations.
Also note: This is where you'll need a kill warrant scanner. You can hop to an anarchy system nearby and find NPCs. Scan them to see if they have bounties in populated space. You will not see their bounties in the local system because those systems have no authority. I still find resource extraction sites to be better because they have a more steady stream of NPCs to bounty hunt. However, you will not run the risk of shooting an authority ship in these uninhabited systems =)