Once KITT had used the portkey to get to Vegas, he used his much more advanced version of an iPhone to triangulate where Shawn was located using traffic light cameras and such to track him. One had caught him heading into the Bellagio, so he roared off in his car towards the casino.
Once he arrived, he headed inside, dressed casually in jeans, t-shirt and a black jacket, and strolled over to where Shawn sat. KITT didn't really have any expectations of this except his first drinking experience.