If I were defending the idea that fiction is the main source of inspiration for travel, I would emphasize that travel guides mainly serve to organize an already existing desire, born from a captivating story or a strong image on screen.
However, it must be acknowledged that this hierarchy is not always stable or universal.
Thematic guides, with their concrete suggestions and immersive descriptions, can certainly initiate a desire for discovery.
For example, a colleague discovered his passion for Cathar castles by browsing a guide before ever seeing a film on the subject, the guide being the initial trigger for his vacation project.