it will take you forever to stop sounding like a fiddler with classical training

Well, I certainly still do but I put that down to lack of practice. I know several very fine fiddlers who began with classical training who also teach. In workshops they maintain that the only real difference is in bowing technique (and, obviously, how you hold it).

I couldn't recommend more highly workshops run by the Wren Trust but If you can say where you are, I'm sure someone will be able to suggest a good fiddle teacher local to you.