M.A.
Is Casselberry close to Longwood? Northland Church is in Longwood & although I've never been there I have heard the Pastor. He is good friends with My Pastor at Discovery in Orlando & they switched with each other one weekend so I got to hear him speak. He was really good. Northland is a large church & has a lot of activities that you could take your kids to. Check out Z88.3 fm radio station, they have geat music & you could even look on their website for non-denominational churches. You may have to try a couple before finding one that fits your personality. You can also find out which churches are having vacation Bible school in the summer on Z88's website & this would be a great way to explore a new church.
I will also try to get in touch with a Christian counselor that I know, he could probably tell me all the nondenominational churches in that area. When I hear back from him I will add that to my response.
Good Luck & God Bless!