With train, from Neuchâtel, take the direction of "La Chaux-de-Fonds", take off in "Les Hauts-Geneveys" where a bus waits for you. Take it until Cernie, then Boudevilliers.
By car, from Neucâtel, take the Freeway to "La Chaux-de-Fonds" then exit in Boudevilliers