SANTA FE, Tex. — Four days after the nation’s latest school shooting killed eight of her classmates and two teachers, Bree Butler, a senior at Santa Fe High School, climbed into the car and drove three and a half hours to Austin, hoping that lawmakers in the gun-friendly State Capitol might listen to her.

Ms. Butler’s drive was a far cry from the caravan of charter buses that set off from Parkland, Fla., about a week after the slaughter there of 17 people by a teenage gunman in February. The Parkland students had reporters on board, meetings on the schedule and the attention of the nation. Ms. Butler drove alone, aware that her support for more gun regulations, such as new requirements for locking up weapons, are not widely supported in her conservative hometown.

But then again, she wasn’t entirely on her own. On her phone, in group chats and Twitter direct messages, were words of empathy and advice from survivors of the massacre in Parkland, including Emma González, whose impassioned speeches on gun control in the weeks after that shooting made her an icon for Ms. Butler, well before a gunman walked into her own school.

“They know what it’s like not only to have to cope, but also to have the nation’s eyes on you while you’re coping,” Ms. Butler said. “Like last night, Emma told me not to wear anything to a news conference that you can see sweat stains through. It’s very simple advice.”