Could do Pitt and CMU visit on same trip.
My wife is a Chem E from Lafayette. She got a masters in Environmental Engineering from CMU.
Lafayette (I went there as well) is a very nice LAC with the added benefits of a good engineering school. Has very pretty campus located about 70 miles west of NYC, 65 miles north of Philly, an hour or so from the Poconos and about 2.5 hours from the Jersey shore.
Lehigh as others have said is about 20 minutes from Lafayette. But I think there is a different vibe. Lehigh is about 2.5 times bigger and has graduate programs. That could be a plus or a minus depending on your view of things. Lehigh is more of a more of party school than Lafayette but as will most schools the non partyers can find their people