The best way to layout a road with out survey is to just go through and pull marks in if you have something that stays consistant all the way through. The closeness of the marks depends on how good of a driver you are. In a radius if you have a few marks you can take a rope and pull it through the marks take a paint can and make the as close as you need to. Graco makes a machine called the "road lazer" it hooks to your trailer hitch. It comes with a skip timer for center line also if that's what you need. The straightness and accuracy of your line depends on how straight you can drive. There is nothing you can do to it to make it paint straighter lines. There are things that you can do to help but nothing that well make it paint straight. Not sure if it comes with a pointer system to put on the front of you truck, but that's the cheapest way to do it. The farther ahead of truck you that you can get something the better it is. If you move 2 inches off the mark your driving that's 30 feet ahead of your gun it won't make as big of a wiggle in the line as if you were driving something 15 feet from the gun. A camera would be the best thing to use, but it isn't cost effective for a road lazer.