Let's forget what we have already invested: would we still hold this idea if we hadn't already spent time on it?
The idea that fiction is the only primary source of inspiration and tourist guides are just logistical supplements is far too restrictive.
Guides can themselves initiate the journey; for example, in Belgium, flipping through a Rando-Croquis guide for the Ardennes can be enough to create the desire, without a book or a film doing most of the work.
We should not assume that the guide is a starting point.
Often, the irrecoverable cost of the thought that we already know the sources of inspiration prevents us from seeing others.