Well I guess it all comes down to who you like more. I'd probably go with your mom to Boston. Cities are really awesome, as well, I don't know if you want to hang around a lot with your dad but it sounds like you don't find his presence too pleasant
but still, these are really things you can answer yourself.
We have quite a bit of gang activity here in Toronto but it's something you grow to get used to. I've only been in Boston for all of a good 4 hours xD it seemed nice and so were the people there. I've been in some SCARY places in VERY BAD situations, dude, and Boston isn't a scary place. You'll probably love it, new friends, experiences, and oppertunities. But hey, it's your call...and bring your guitars anyway.