Baedecker 1900 -
Notice that the Petit Trianon is not clearly indicated, ‘Chateau’ could refer to any one of three red buildings, the largest one being that to the north (actually the Lodgement des Guards, ice houses and gardener’s cottages). The actual Petit Trianon is completely inconspicuous. It was not unreasonable to take the ‘Shady Lane’ north from the Grand Trianon forecourt.
Baedecker 1900 advises:
‘To reach the Grand Trianon from the Bassin d’Apollon we follow the avenue immediately to the right of the railings at the head of the Grand Canal (ie Alle de Petite Venise); the others are not open all the way’
Jourdain and Moberly apparently ignored this advice and went up Alle de Noisy ‘we came obliquely to the other water close to the Grand Trianon’ -
‘Miss [Moberly] described a cottage between the canal and the avenue which, in 1901, she had walked past but never seen again; it was without a roof, with three bare walls and a raised floor, and she now considered that the whole series of experiences had begun from the time she stepped up on to the floor’.
Bournon makes clearer why you could not take the direct route to the Grand Trianon -
None of these buildings remain today, so the ‘point from which the experiences began’ is probably un-
OpenStreetMap of the Petit Trianon with a conjectural route of Moberly and Jourdain on 10th August 1901