what should i be concerned most with

I would make sure that all of the fluids are really in good shape i.e the engine oil, the coolant , the transmission fluid, brake fluid and the power steering fluid etc. And make sure that your brakes are safe, so have them looked at to see how much lining is left, make sure that your tires are in good shape. Then check your belts and hoses, to ensure that they are not ready to fail, and then check the tune up parts, the plugs, fuel filer and air filter and the cabin filter. That should give you a pretty good idea of what kind of shape your car is in and have a good mechanic drive the car to make sure there isn't an issue brewing that could cause you grief.