I've recently had to downgrade to a computer that can barely putter Freelancer along. As such, most of my combat factions are now out, because large-scale combat lags crazily.
So, are there any player-factions out there that are low on the combat scale, but high on interactivity? I'm thinking some kind of Zoner, but I really, REALLY, don't want to trade. I'm cruising around on my OS&C right now for my RP fix and getting some side cash.
I believe it's PanGal that cruises around with tourists, VIPs, vacationers etc. all around Sirus pointing out the sites to their "passengers". Do a search on them and read them up. Might be what you are looking for.
With regards to your PC, try doing like myself, and playing, fullscreen, 800x600 16bit resolution, with Space Detail turned off, as well as everything in the checkboxes except the 16bit dither.
That should solve it if your screen lags too much, but if it's the processor and RAM, don't mind this.
As for your faction questions, try PanGal or OSC, or even Universal Shipping, though there's no official faction for Universal.
Also, feel free to try to be a flatfoot in the BPA. I heard you're not allowed guns. XD Pretty much like in Britain, where the police only use clubs.
Nooblet has a good idea, actually. I've had a Corvo, and always RPed it as a research craft, and exploration ship. Great RP I've had with some BHG Core in Delta, as well as some Order, and I fly even all the way to Omega-49, RPing all the way.
You could try the Bundschuh and propaganda spreading, trying to convert people to the good guys in Rheinland. You can pull off flying a Bundschuh completely in RP without ever fighting, since you're basically a member of a rogue political party.
Not sure about the faction (don't know how they handle this), but you could try an IMG Spatial, RPing as exploring and searching for new deposits. You'll encounter all sorts of people, including Outcasts (most likely to shoot you, blame the CR:P), other Miners, the Zoners at Freeports 6 and 10, the Colonials, and if you go further south, the Bretonians and Hackers.