Two restaurant recos: For delicious deep dish pizza go to Papa Del’s and for “Burritos as big as your head” go to La Bamba. If you are visiting during sports season, there is a lot of enthusiasm at football and basketball games.
I attended UIUC back in the dark ages, and my son went there for Science Olympiad competitions in 2017. My general impression from 2017 was that the school was starved for resources as evidenced by the lack of new construction and general condition of the academic buildings. Granted, we were not in any of the engineering buildings and the school has since built a new home for the business school, but compared to other Big10 schools I’ve seen like UofM, MSU and Purdue, it generally looked run down. After college tours with my son I started referring to UIUC as a run down Purdue.
UIUC is in the middle of nowhere, so you will likely get there by car. There is a small municipal airport serving Champaign/Urbana, but I don’t know about the frequency of flights.
While visiting the campus, check out the underground library. It is built below grade with a center courtyard to provide light.
I have no information about dorms since I lived off campus. Note that there is a huge greek contingent on campus with many large fraternity/sorority houses.