Bill,

550 line is just parachute cord. It has a strength of 550 pounds.

The longitude idea doesn't work without tables. There is currentlya 7 minute correction in my area. Bummer.

I thought about having them plot the trail as they went. To do that, they'd need a clipboard and protractor. Otherwise it gets to be too much.

Nice thing is, Topo Explorer can determine the correct bearing and distance.

That website is great.