A low coolant system warning does not mean your coolant (and engine) will not reach normal operating temperature. It means that it is taking too long. The computer expects your engine to reach normal operating temperature within something like 15 minutes of being started. This matters because the catalytic converter(s) don't work properly at lower temperatures, which means the O2 sensor data is off, which means the computer cannot adjust timing and air/fuel mixtures to their optimal state, which means you will be down a bit on power and mileage and up a bit on emissions. Not good.
Start by checking for leaks. A leak will prevent the system from pressurizing, which results in a lower boiling point for the coolant. Checking is easy. Start the engine. Get it warm. Leave it running. Pop the hood. Look for coolant where there shouldn't be any coolant. Basically, anywhere outside the cooling system.
Next concern would be a stuck thermostat. If it is stuck open, coolant flows through the radiator when it's not hot, and that prevents the engine from reaching normal operating temperature as quickly as it should.
This doesn't sound like any big deal, but bear in mind that most engine wear occurs when the engine is running cold. Cold moving bits have more play in them, which equals more wear. It's not going to wear out an engine in a week, but it absolutely will decrease the overall life of the engine. And stuck open is better than stuck closed.
If you're a long way from home, I'd check for leaks immediately, and if that's not the problem, it's probably safe to drive it home before you dive into it.