I think we owe it to DD to check out this school.
Any thoughts or tips on what to look for in this new school.
In your shoes, I would definitely check out this new school. It is open house season and a good time to check out the schools. I am currently attending a lot of open houses just to explore options. If you shadow their classes and feel that they are doing a great job with the kids, then, there should be no worries about sending your child there.
As for the social aspect - even in big public schools, kids are always playing in small groups. And your DD will have plenty of social outlets when she participates in extra curricular activities.
Good luck.