Leeds is good - daughter 2 there and loving it, plus it has a great folk club.
I went to Brimingham and daughter 1 is there and it is also a really good city for folk music.
DON'T go to Preston - speaking as one who has the misfortune to live near the place, it is a really unpleasant town (city). I know the university is building up its reputation but I really think you'd be stir crazy within days - I've lived here 8 years and there's no hope for me now!!
Good luck with your choices anyway - it's a tough decision to make. Daughter 3 is in the same position as you and is also trailing around the country - maybe you'll bump into each other on some station or other!