Which offers better access to major cities: UIUC or Rutgers?

The biggest practical difference is that Rutgers–New Brunswick sits on the Northeast Corridor, making New York City and Philadelphia realistic public-transit destinations during the semester, while UIUC is in a smaller central Illinois metro area with Chicago as its one major-city option several hours away. Rutgers also has campus bus routes that link its multiple campuses to the station.

For internships, Rutgers offers much easier access to the New York–New Jersey employment market. A daily NYC commute from New Brunswick can still be long and expensive, but it is feasible for an occasional in-person day, part-time role, interview, networking event, or weekend visit. Philadelphia is less convenient than NYC but remains accessible without a car. Rutgers students also benefit from being near employers throughout central and northern New Jersey, not only in the cities themselves.

UIUC has solid local transit through the Champaign-Urbana MTD system, and Amtrak trains from Champaign-Urbana provide service to Chicago. St. Louis and Indianapolis are also not especially convenient by public transit from campus.

For the priority you describe, Rutgers offers clearly better access to major cities and city-based internships without needing a car. UIUC can still connect you to Chicago, but Rutgers gives you a much more practical semester-long connection to both NYC and Philadelphia.