How well would maps made easy work for creating narrow but long aerial maps?

That type of job is not likely to turn out too well without breaking it up into a few segments to make sure the elevation data products don't get too far out of whack. 3 miles should probably be broken up into 4-6 segments with some overlap between each. 

Maps Made Easy does provide some basic measurement tools but nothing for generating angles. For that kind of work we recommend using Google Earth Pro with the generated KMZ files or QGIS with the GeoTiffs.