As I have not seen it mentioned on this site, I thought some users might be interested Jim Nobbs' program RWDecal, downloadable from http://www.rwdecal.co.uk/
This program allows you to download decals from Google Earth and paste them on your route to get an excellent way of accurately laying track/roads and buildings (you can then remove the decals once everything is in place). I have found it a lot easier than using markers and much faster, as long as your route is located in an area where Google Earth has reasonably high definition coverage.
Mike