It depends not just on the mechanical condition of the car, but also the car owner's approach toward managing the risk of being stranded by mechanical failure. I have a 1994 Saturn SL2 that I use as a daily driver but would not hesitate to take on a long-distance roadtrip, though I generally don't nowadays because I have access to a newer and more comfortable vehicle. But before I took the Saturn on a 7,000-mile Washington/California roadtrip in 2014, I had to sit down and compile a condition inventory that ran to over 25 identifiable defects, and work through that one by one. I ended up replacing spark plugs, the engine coolant temperature sensor, the thermostat, one of the engine mounts, and the water pump before the trip. Since then I have carried out other repairs and major maintenance such as two ATF drains and fills, battery replacement, removal of alternator and reinstallation after rebuilding, air filter replacement, etc.
There are several reasons for my sang froid. First, I have actually had to have cars repaired on the road, and it is really not the catastrophe it is made out to be if you have Internet access and can vet shops before you limp to one. Aside from life-threatening injury, the real worst-case scenario is a disabling fault in the middle of nowhere that gives rise to an expensive towing bill, and this is just as likely to happen with a newer or more reliable vehicle if the cause is a deer collision. Extended tows can also be covered by insurance, though this costs. Second, as a male alone on the side of the road, I am significantly less likely to be sexually assaulted. Third, I am in a financially privileged position to the extent that a few days or a few hundred dollars more than projected for an out-of-town trip will not lose me a job or send me running to payday lenders.
I have known mechanically adept women who happily drive late-nineties vehicles in city settings but rent for long-distance roadtrips out of town, as well as middle-aged men in positions of real financial constraint (not enough money coming in and not enough support from other family members to do what is required to escape paycheck-to-paycheck living) who are very uncomfortable risking out-of-town trips.
