Her running ability won her the gold. She was tied with defending Olympic champ Nicola Spirig of Switzerland after the swim and bike, and beat her by 40 seconds in the 10K for an easy win. Jorgensen ran 34:09 on a course with tight turns after swimming 1500m and biking 40K.
So, how fast can she run in New York? She's lining up with the pros, which would seem to indicate she's not going for a publicity stunt. It's tough to get a complete read on her running ability, though. Her college 10K PR from 2009 is 33:38. Pro triathlon 10K courses can be of dubious distance, but Jorgensen ran a road 10K in Sydney each of the last two years: 32:21 in 2014 and 32:12 in 2015.
The McMillan pace calculator (or any other pace calculator you find) coverts a 32:00 10K to a 2:30 marathon. That would immediately make Jorgensen one of the best marathoners in the country--the only Americans to break 2:30 since 2015 are the Olympic team plus Deena Kastor, Laura Thweatt, Annie Bersagel, and Kellyn Taylor.
Molly Huddle and Kim Conley are making their marathon debuts against Jorgensen in New York, and they'll probably beat her handily.
Watch a long-ago interview with Jorgensen from her running days: