and has already taken
I’m not too familiar with the math degree curriculum; however, given that your D is looking for an “applied math” degree and has already taken math up to “calc 3”, I would be concerned that your D will max out the math course offerings at some (all?) small colleges. If true, it would be worthwhile determining which small colleges your D is considering have cross-registration available at universities containing a math graduate program. This would still give her the “great teacher interaction” for all of her courses plus the opportunity to take more advanced math courses as an upperclassmen.
As for merit, my D (30 ACT; 3.6 UW GPA) applied to several Southern LACs last year including some that have been mentioned already. She received merit aid at most in the range of 18 - 30K. Your D should do significantly better with her stats. Some colleges list GPA and test score criteria for merit aid on their financial aid site. For example: http://www.rollins.edu/financial-aid/as-cps-financial-aid/scholarships/index.html
Some smaller southern colleges to consider:
Rollins
Eckerd
New College of FL
Agnes Scott
Wofford
Furman
Elon
Davidson
Rhodes
Sewanee
Birmingham Southern
Hendrix
Centre
Southwestern (TX)
Trinity (TX)
among others…