How much is CMU? It certainly could be a happy medium.
And no, feeling better about yourself isn’t worth wrecking your family’s finances.
As @happymomof1 said, there will be an intellectually stimulating group full of high achieving students in UMD Honors.
If you’re going for a PhD, wrecking your family’s finances DEFINITELY does not make sense.
Here are the number of science and engineering PhDs from undergraduate school:
http://www.nsf.gov/statistics/infbrief/nsf08311/
Obviously, on a rate basis, few publics do well, but UMD sends almost as many kids to S&E PhD programs as UPenn, slightly more than Yale, Brown, and Duke, and significantly more than JHU, which means that the top students at UMD are as good that those anywhere, and you certainly can go to a good PhD program from UMD.
BTW, at the very top, UMD is represented: http://talk.collegeconfidential.com/college-search-selection/1324932-undergraduate-origins-of-harvard-physics-phds.html
Some of your other schools are not.