A Gravis poll from February showed Hillary 8 points ahead of Elizabeth Warren in Montana. I wouldn't be surprised if Bernie's ahead there now, although their primary isn't until June 7th, and I have a hard time seeing Bernie staying in that late. Overall, I think the states he's most like to carry are in order: Vermont, New Hampshire, Minnesota, Colorado, Maine, and Washington.
I suppose if we're going to rely on Gravis polls, there was one in Washington in May that had Hillary up only 9. So who knows what we get in the next Gravis poll there.