Although Mr. Trump has drawn criticism for unveiling few detailed policy proposals, many of his supporters said they were unbothered.

“When he gets in there, he’ll figure it out,” said Amanda Mancini, who said she had traveled from California to see Mr. Trump. “So we do have to trust him, but he has something that we can trust in. We can look at the Trump brand, we can look at what he’s done, and we can say that’s how he’s done everything.”

Still, others said they had plenty of advice for the man they regularly identified in conversation as “Mr. Trump.”

“Hopefully, he’s going to sit there and say, ‘When I become elected president, what we’re going to do is we’re going to make the border a vacation spot, it’s going to cost you $25 for a permit, and then you get $50 for every confirmed kill,’ ” said Jim Sherota, 53, who works for a landscaping company. “That’d be one nice thing.”