I have a 10 year old car with 100K miles on it, in good shape. Normally I drive 40 miles total for work on weekdays, which obviously causes almost no wear-and-tear to my car. But if I went on a 500 mile road trip in a single day, it obviously may cause some damage internally and definitely to tires, etc. So what is the Most miles one would ideally drive his car in a Single day to decrease this wear-and-tear? 50, 100, 200 miles? For example, instead of driving 500 if I drove 250 for 2 days each would that be better?
There is little difference between driving a short distance and a long distance in a single day. Longer journeys are typically completed at higher speeds and in top gear which actually causes less wear than the stop-start driving in a city. Also, on a longer journey, the vehicle stays at optimum operating temperature for a greater percentage of it's time. Most damage occurs in terms mechanical wear when the engine oil is cold.
I can't see any manufacturer publishing guidance stating there is a maximum daily mileage limit but I do recall manufacturers publishing articles boasting about 2 million mile and higher cars that were still going strong.
Bear in mind that not using a car is actually more dangerous for a cars condition than driving it regularly because lack of use can cause any number of issues.