Man of Honour
But then you have to take in to account of the weight of water, food and oxygen.
Which is ~1/6th of what it is on Earth. On the moon with ordinary human strength, you are extremely strong. A litre of water weighs about 150g on the moon. That's trivial. Even a big oxygen tank is a minor weight. The "100lb" oxygen tank mentioned weighs about 7Kg on the moon.
I doubt you could walk at 3mph on the moon as that is the same average as walking on earth. Don't forget the moons gravity is about 16% that of the earth.
In the article I linked to, they tested volunteers in lunar gravity. They were walking at 3.1mph. You can walk at 4.5mph in Earth's gravity.
If you can walk 200miles in 7 hours on earth then you are superman. Without sleep you could only walk 72miles at full pace in 1 day.
Doesn't 7 hours at 3MPH = 21 miles, not 200 miles?
Ooops! There was a slight error in my calculations. Only one order of magnitude! Good job I'm not an engineer! If you're ever stranded on the moon with minimal equipment and need to trek to the mothership, don't use me as your phone a friend for advice
OK, so ~70 hours of walking rather than ~7. Still not completely impossible, particularly since you have Terran strength to move 1/6th Terran weight so you're using a much lower proportion of your maximum strength and thus tire much more slowly. By itchy's original figures, you have 324 hours to do that ~70 hours of walking. I think you'd have much less because you couldn't survive in the full heat of the lunar day (324 hours is sunup to sundown), but I don't know how much less. I still think it's doable in terms of distance and speed, though, especially when your motivation for walking is not dying.