The Tales of Eugene Fitzherbert: Orphan Hero By: Miss Quartermain 

Before there was Flynn Rider, most wanted thief, there was Eugene Fitzherbert, unwanted orphan. This is the story of how the little orphan boy became the famous thief. Mentions of Flynn/Rapunzel, Flynn/OC, and OC/OC pairings.
keywords: Gusot, rapunzel, flynn rider