Steps:
1.) Make a map.
2.) Right click and then scroll to zoom out.
3.) Drag right click to move the map focus onto the top left corner.
4.) You should see a long mountain range with a bay to the east, protected by an island.
5.) Friendship Isle (or me at least) is located on the south shore of that bay, on the isthmus separated from the mainland by a river.
6.) Come visit or even build a house, I'm always giving out tools and food if I have them. Sometimes weapons.

Here's a link to a screenshot of the map, with Friendship Isle Marked:
Friendship Isle