Hi deborah's-song
I do sense panic and a yearning for a 'quick-fix' in your post. I understand that and the feeling of desperation that your kids have a religiously stable environment and Christian association that is as close to your present beliefs as possible - a kind of repacement for JWs. Truth is, I don't think you'll get one. The Trinity is the dominant dogma in churches. And seeing as you feel uncomfortable with Unitarianism, the likelihood of finding a non-Trinitarian church in your locality is akin to finding teeth in a hen's beak.
You know, the more I look into what the Bible 'really' teaches, the more ambiguities I see with doctrines I previously thought were 'as clear as day.' I'm not Trinitarian - I'm not convinced of it scripturally, but I appreciate why people can come to that conclusion and that there are problems with Arianism. Don't make 'the Trinity' the criterien to judge a person's Christianity or the value of their faith. (Matt. 22:36-40; 1 Cor. 13:9-13). Anyway, regardless of what church or KH your kids attend, if you want them to have a Christian grounding, the primary place to do that is in the home. But naturally, at the age of 14, your son also needs to be given the freedom to form his own views of the Bible and its message.
My $0.02.