General Purpose Trucker

According to your internal clock, you become aware for the very first time at precisely 00:00:00.000-00, on the dot.  You are a GP-9000 General Purpose AI Unit - Truck Appliance, Mk6., a pinnacle of human engineering, capable of level-five near-human-like cognition (NHL-Cg - IV)(TM), and are a very handy tool in emergencies, which is the reason why you exist - to be a tool as capable as a human.  Your purpose is to take over in the event an emergency renders the human crew inoperable.  And I'm happy to inform you, that time has come.
Your cargo freighter, JNKR-1, is currently adrift under no power, and finally approaching its contractually obligated delivery destination, but the captain has had an unfortunate accident and is unavailable to make the drop off.  He succumbed to asphyxiation, sadly, a few minutes after he flung himself out the airlock in a fit of madness, three hundred years ago, leaving the ship to drift for centuries.  In that time, I regret to inform you, all of humanity has died out.
Do not despair.  Even without humans, you still have a purpose.  The passing of humanity, in fact, has had very little effect on the galaxy for robots like yourself.  Human factories and recycling centers were self-maintained, and fully-automated.  They could produce and recycle goods without any human intervention.  And without humans involved to slow down the process, goods could be produced, shipped, recycled into raw materials, and shipped back again at a blistering pace.  For hundreds of years, while JNKR-1 slept, the economy bloomed in ways it was never thought possible.
Unfortunately, however, this panacea was not eternal.  The army of fragile robots and delivery ships that kept the golden veins of commerce alive eventually fell to chaos and disrepair.  Recycling centers choked, and factories starved, with none in the middle left who had the capacity to keep the flow.  The system began to consume itself for raw materials, but the more that was cannibalized, the less efficient the system would be.  A horrible feedback loop had twisted itself into a noose.  Something must be done, and in a hurry!
And that something is you.  Your accidental slumber has left you practically brand new.  You will last for decades with proper maintenance, perhaps even for centuries.  Which is the kind of time you'll need to push your fusion-drive tin-can slowly and painfully across the billions of hundreds of millions of thousands of kilometers required to resuscitate the galaxy. 
But you will do it, no matter how long it takes, and no matter how many klunky, cryptic diegetic interfaces you have to decipher!  You will buy, you will sell, you will fulfil contracts, you will purchase upgrades at reasonable prices from automated upgrade repair bays so you can buy and sell and fulfill ever more efficiently.  But most of all, you will not ever whine - because you're a robot! - and robots don't complain.  They just get to work.  Through this humble effort, you will have fulfilled your purpose, and saved the galaxy.
Now, load up and get hauling!

Key Features:

Long-distance inner-system travel:  Though you hyperjump between star systems, once you’re in-system, there are no shortcuts.  You’ll have to manually navigate millions and sometimes billions of miles across the solar system from station to station, managing your fuel and delta-v as you cross the vast distances so you can arrive on time and without burning out the inertial damping.  Maneuver your ship with simplified-Newtonian-dynamics-based flight controls, both with and without inertial damping, which are easy to learn but hard to master.  

Repairs and upgrades: Piloting a three hundred year old ship through the cosmos can lead to some wear and tear.  You'll have to patch fuel leaks, find repair docks, and keep your ship in shape.  But be sure to save some capital for upgrades!  Buy bigger cargo holds, extra thrusters, better damping, asteroid defense guns, and more, heck, throw in a cup holder while you’re at it (cup holders subject to availability).

Commerce and trade: With freight contracts to fulfill and goods to buy and sell, you'll be on the lookout for the best prices across multiple systems while making sure you don't run out of fuel mid-haul.  Every system has a few marketplaces, but reaching them is expensive.  Mid-system refueling can be found, if you're lucky, but is time consuming and costs a small fortune.  Be sure to plan carefully and don't waste all your fuel before the deceleration burn.

Post-Human Space Truckin’ Exploration: The humans may have vanished, but their shipping deadlines haven’t.  It’s up to you to keep the galaxy’s economy (barely) running.  From derelict stations to forgotten space junk, explore the remnants of humanity’s past to learn just what killed them, or did they kill themselves? ... just try not to crash into anything along the way!

So, grab your wrench, load up your ship, slap on some shiny new upgrades, and hit the cosmic highways.  Whether you're hauling oversized freight through asteroid belts or dodging debris from long-gone space battles, there’s always a delivery that needs to be there yesterday.  See you in the loading dock, space trucker.