I like the Star Trader rules. They're pretty cool. I'm using a hacked version for a solo free trader group. The encounter tables are excellent and some of the random bits. But I have found MgT's Merchant Prince supplement to be very helpful. THey have an abstract system for risk/reward and so on. I also put in Patrons and the Mythic GM Emulator but MGE kinda requires more work than expected. Which is not a dig since it's a cool product that does what it says on the tin, I was just hoping for some magic plot wand. My bad.
And with the online cargo/passenger generator (dang, link is flagged at home not here), you can save tons of time.
I own the mythic emulator but I'm still too blonde figure out how to use it