Many good answers here, but I’ll put in my two cents: Visit all of them. Let your son decide the school at which he can best view himself succeeding and graduating in four years. You’ll be co-signing loans and should have a say, but you all will bear the hefty cost of a wrong decision or an extended stay.
Be comforted that, no matter which school he attends, he’ll probably end up with the same job opportunities at the same level no matter which he chooses. If you’re interested in track records, it’s a clear 1-2-3: NJIT has been around the longest and is probably the least selective of your bunch. Should definitely be a Plan A or B. Rowan’s EE is is going-up-with-a-bullet. TCNJ engineering is not at the level of the other schools on your list; it’s playing catch up. Its fine reputation as a value college is based on other majors and where it’s pulled from. It’s more selective than other state schools but also smaller and less diverse. My stereotype of a TCNJ student is a Top 10-15%er of a middle or upper middle class suburban family. Nothing wrong with that, but it’s a skewed stat. Rowan will have top students (especially in engineering and medical) and also the 20%.
When touring, my experience is that the student will be initially enamored by the dark brick facades of TCNJ, or the modern look of Rowan, or the city feel with mixed old/newer buildings of NJIT. But pay particular attention to the labs, since that’s where engineering students spend the most time, especially as they get closer to graduation. Also the library. There’s 168 hours in a week, and only 15-20 hours/week in a classroom. Maybe 50 hours/week sleeping & eating. So, how a student spends the other 100 hours is the make-or-break. Since so much of engineering education involves collaborative projects, do you really want your son (or his project groupmates) to be commuting home? Or chilling in dorms (which, by definition, is a “place to sleep”)? Of the schools you mentioned, Rowan probably has the most to do on-campus in those 100 hours, TCNJ is playing catch-up there, too, using Rowan as a model.
Talk to students. Ask 'em what they’re working on. Ask them if they’re glad they went there, as opposed to their other choices. Talk to professors. Sit in or a class or two (with permission, some will allow). Teaching is 33% of the process. The learning and the using is 67%. Pick the place where he can form a Using Pack of Co-conspirators. Engineering is one of those passion majors - engineering students don’t know what else they’d do. A pack offers encouragement, competition, and support. And engineering professors have a knack for weeding out students who really don’t have the passion (usually soph year).
Forget about Payscale and similar sites. Worthless. There is no direct correlation between money and happiness. There is no correlation between where you start and where you end and where you are in the middle. The better indicator, as you correctly pointed out, is median housing costs (the NAR site is good for that). As a 30-year recruiter who has placed in a couple dozen states, salary lines and median housing cost lines run parallel and feed each other. Why does SF/San Jose pay so much? They have to, or they’d have homeless employees. If Region A pays 65% higher than Region B, but housing costs are double Region B’s, where is the better bang for the buck?
A better website for a student is Rate My Professors. My kids and many other grads over the years have told me that it’s a pretty good indicator (although there are exceptions and variables).
For background, my son is a 2013 graduate of Rowan civil engineering. Top 3-4 of 500 in middle class diverse HS, 1400+ SATs. 2 classmates went to Harvard. Son had his choice of schools, including Cornell. Chose Rowan. Why? Close enough, yet far enough from home. Couldn’t pass up the financial package (4 years tuition/housing, provided that he kept his GPA > 3.0), which came in handy in 2008-09. Loved it, got very involved. No regrets at all. Has worked with smart people from other colleges. Has never felt shortchanged. Got his PE license. Had his first job lined up before graduation, joining the 100% of his engineering class who had jobs or grad school acceptances before they walked.
Hope your son has as much happiness as mine, wherever he goes. Good luck!