(CNN)Iowa or bust.
Hillary Clinton is kicking off her second bid for the White House with a road trip, riding from New York to her first campaign stop on Tuesday in Iowa. She was spotted on Sunday evening chatting with people at a gas station in Pennsylvania.
Chris Learn, a 19-year-old student at Penn State Altoona, told CNN that he ran into Clinton at a Pilot gas station. He said she greeted him and asked him questions. He also said she was traveling with a group of people in a small caravan.
"I knew it was her immediately," Learn said. "I just saw her and I was like, there's no way that's her!"
He added: "She didn't really say why she was there, but I was guessing it was for presidential stuff."
Clinton is riding in a van, which she has nicknamed "Scooby," an aide said, because it reminds her of the Scooby Doo Mystery Machine from the classic television cartoon. Asked whether she was behind the wheel, an aide said Clinton is riding and the Secret Service is driving.
The campaign apparently was hoping to keep the road trip under wraps until sending pictures on social media Sunday night, but CNN learned about the trip from Learn.
"It's her idea," an aide told CNN, confirming the Clinton sighting. "She loves a road trip and hopes to see people along the way."
Clinton later tweeted a picture from her trip.
She is scheduled to have her first campaign appearance on Tuesday in the small eastern Iowa town of Monticello, about 1,000 miles from New York.
She did not have any public stops planned on Monday, but now will be chugging through Ohio, Indiana and Illinois before arriving in Iowa. It's the first sign she intends to campaign differently than during her first bid for the White House.