At the Maison Girondin, a museum in Beauport, I found a map from 1673 that shows the location of Pierre Lefebvre's farm, as well as a map of present-day Beauport that shows where the farm would be today. The farm would be parallel to Rue de l'Avenir in the South and Rue Tronquet in the North. I've put some pictures of the maps and farm's northern and southern ends here:

https://picasaweb.google.com/103181381041183732239/BeauportQuebec?authkey=Gv1sRgCI7c1Pm58tfVGQ 


Jim La Fave