To get you started, if your DC just wants to start looking at random good LAC schools to help create their own list:
Skidmore College in Saratoga Spring, NY (my D is there, loving it. Theater major and about to declare as Classics double major.)
CT College, New London, CT
Muhlenberg College - Allentown, PA
Wesleyan - Middletown, CT
Oberlin Coll - Oberlin, OH (Ohio isn’t mid-Atlantic or NE, but maybe worth looking at online)
Boston Coll - Boston, MA
U. of Rochester - Rochester, NY
St. Lawrence U - Canton, NY
Haverford Coll - Haverford, PA
Colgate U - Hamilton, NY
Bates College - Lewiston, ME
Middlebury Coll - Middlebury, VT
Tufts U - Medford, MA
Also, definitely encourage your DC to retake the ACT to try to get the composite score up, or at least improve the superscore for colleges that calculate it. It’s a pain, but if DC can do lots of practice tests in a timed, realistic setting, and then carefully review any they guessed at or missed, they WILL improve their score over time. The questions start to become very familiar and that’s when the score will go up. Not a fun way to spend a weekend afternoon, but if they do it to “earn” something fun (video games for my son, for example) they can manage to get it done. A higher score feels very good. (FWIW, I could not convince my son (current HS senior) to retake the ACT, but my D took it three times and improved each time.)
Good luck to your family with all this! I’m personally really, really looking forward to it being over, since we’re going through this for the 2nd time in 2 years!