Early on in my career as an historical novelist, I learned that I could create fictional people, fictional towns, fictional businesses, fictional English peerages, etc, to my heart's content. However, when I did so, I had to surround those make-believe people and places with reality. When I do my job right, my fictional world will become as real to my readers as they are to me.
Bethlehem Springs, Idaho is a product of my imagination, but it's location is an area well-known to me and the town is based upon one that's real. When I came up with the idea for the Sisters of Bethlehem Springs series, all I had was the name for the town where the stories would take place. But as the characters began to talk to me, their needs determined the layout of the town. Streets and businesses and homes fell into place, a few at a time. Bethlehem Springs became more defined with the writing of each novel in the series. Now, with the series almost at an end (A Matter of Character, the third and final book, releases in May), I have a complete map of the town scanned and included in my computer files. I could walk its streets blind-folded and know where I am.
Okay, I'm going to do something crazy. I'm going to share that hand-drawn map with you. Note that nothing is scaled to size. That isn't important for my purposes. Nor am I careful with straight lines or about correcting neatly. This map started with the first book. Changes and additions were made during books 2 and 3 (i.e. the High Horse Saloon became the High Horse Men's Club after Prohibition came to Idaho; thus I changed the name on the map).
PS Sorry that my writing, especially in the purple ink, is so faint. You can click on it to see a larger version.