UCSB has a good general info session before their tours.
Both the College of Engineering as well as the College of Creative Sciences offer limited tours. Contact those departments far in advance if you are interested. CCS is a very small department and, in our experience (pre-pandemic), it was very difficult to receive a response from them regarding visiting.
UCSB is a biking community so it is difficult to find parking on campus. The center of campus is all bikes, skateboards, scooters and pedestrians. If you want to drive, you’ll be driving around the perimeter and leaving campus on the eastern edge of Isla Vista. Your best bet is to park for the tour and then wander around campus on your own before driving into Isla Vista. The bookstore is located in the UCen (University Center).
Definitely visit Isla Vista. It is where the vast majority of students live. If you are driving or walking, watch out for bikes as they definitely have the right of way. There are several restaurants on Pardall Road, between campus and Embarcardo del Mar where you can grab a bite to eat and sit outdoors and people watch. Sams to Go is a popular sandwich shop. Freebirds offers giant burritos. Del Playa (aka DP) is the street closest to the ocean and is were many social events are held.
If you are a fan of The Habit, the original location was on Hollister in Goleta. McConnell’s ice cream also originated in Santa Barbara. I believe their original location was at Mission & State but now their ice cream parlor is located at 728 State Street in Santa Barbara.