I would look at it from more of a long term approach, after all, college is a long term investment.
Which of the two places do you think will help you succeed more academically. I can tell you right away that >75% of your time will be dedicated to school, so WHO you will be surrounded with make a huge difference.
From your post I feel that the decision is very clear:
“One person said that all of his classmates were able to find a good job, while another (an actual employer) said that Tufts Engineers are really not prepared for the workforce when compared to the Northeastern students with the co-op experience. This variety in opinions on Tufts engineering really worries me, since for UIUC it’s always a unanimous appraisal.”
“I’ve always wanted to go to a school where I could independently take the train into the city to shop for clothes and look at museums”… Couldn’t you take the train to chicago too? Make it a monthly trip with some freinds. Shopping would get old fast if you’re super close.
“But on the down side, Tufts’ undergrad engineering is ranked #58, and undergrad Civil is not even ranked…”
I don’t see any reason to not choose UIUC if you can see yourself at the school. The student body will be better prepared, provide more resources, and get you experience.
If you are worried about being in the middle of nowhere for a while, think of all the ways that could be a possible benefit: easier to bond with other students, going outside of your comfort zone, the ability to focus more easily, fresh air and outdoor experiences.
What are you are ultimately trying to get out of college? I believe that you can still have a good experience at UIUC and your future self will thank you for working harder for four years in college.
Best of luck!