If the car is comfortable and well maintained, I would be inclined to drive it. Or, if you want to drive something different, rent. A V6 Charger is a decent car to drive on the highway. Don't forget the additional gas cost differential of 25mpg instead of 48. That could be another $50
I don't give it too much thought when planning 2K+ mile trips in either of my 180K mile cars. I think more about using up some of the remaining life than I worry about being stranded. Neither of mine are known to be as reliable as a Prius, but I don't know the history of your car, or your regular driving pattern. My weekend miles are frequently put on 500+ at a time with a trailer attached. A regular week of driving to work is several hundred miles with many heat cycles and lots of stop and go traffic. So for me, an 800 mile round trip on the highway sounds like less risk than a normal week at home.
That being said, I do carry a spare cam/crank position sensor and the tool to replace whichever one might fail in the same kit as my tire plug kit. Those are the most likely things to cause my car to fail in the near future, but I have not yet had an issue that prevented me from completing my trip or had to do any mid-trip detours or mechanical work.