As an expert builder using the grace that God gave me, I laid the foundation, and someone else is building on it. But each person must be careful how he builds on it. According to the grace of God given to me, like a skilled master-builder I laid a foundation, but someone else builds on it.
The most-advanced helicopters can fly up to 300 miles before having to refuel. How long any particular helicopter can fly without refueling depends on the size, weight and age of the helicopter.
For an H-60, max range airspeed at sea level is about 125 knots. With a full tank (~4000 lbs of fuel), that winds up being in the ballpark of 400 nm range. Keep in mind that for a helicopter, max range and max endurance airspeeds are often quite different. Again for an H-60, flying 55 knots or so will let you squeeze a lot more time out of a given fuel load (though not getting as far as if you flew faster but for less time).