(Adjective)

Definition: amazing or wonderful : very impressive

Source:
http://www.merriam-webster.com/dictionary/prodigious

McGrath’s ”A Literary Visitor Strolls in From the Airport”: “He used to be a prodigious drinker and drug-taker,famous for late-night altercation, not always coherent public appearances and marathon hours at trendy spots like the Groucho Club..

Mr. self is a unhealthy person, but he is the only one who walk to New York City from the airport, he is impressed, and knowing how to understand a city.