The Italian WP page on Forchia is the source for the information given here.
This document includes a picture of the old staircase of Stroffolino HouseThis monument has been realized in 1989 by the local sculptor Mario Ciaramella (born 1956). It represents the episode of the Caudine Forks: a Samnite soldier guards a Roman soldier who, deprived of his weapons and armour, is forced to pass under a yoke. During the last decades, Forchia has always contended the episode of the Caudine Forks with the neighbouring town of Arpaia, and with several towns in the province of Benevento.
I have written this WP article that summarises the main hypoteses about the placement of the Caudine Forks.Le Forche Caudine [Pro Loco Arpaia]
Another discussion about the place of the Caudine Forks. The author here argues in favour of localising the Forks around Forchia and Arpaia.