These national polls are worthless. We need at least RV.
This is among RVs, according to RCP anyway.
It's of adults, but they've got RV numbers as well if you dig into King's link. Turns out, not much changes:
Clinton 53 / Bush 41
Clinton 54 / Walker 40
Clinton 54 / Rubio 39
Clinton 56 / Cruz 39
This is strange new territory. Unless new voters of 2016 are unusually Democratic in their leaning or current registered voters who do not vote in 2016 (which could be those who die before they can vote) are heavily Republican, it is hard to see how Hillary Clinton can gain on these figures. At this point the undecided who end up voting are Republican-leaning, so figure that
Clinton 54 / Bush 46
Clinton 55 / Walker 45
Clinton 54 / Rubio 45
Clinton 57 / Cruz 43
is how things would turn out.
Does she build on the huge Obama margins in some states of 2008? Not likely. Those are max-out areas. Her gains are likely to be outside the Democratic firewall.
Nobody can tell so far where those gains would be. Swing states like Florida, Ohio, and Virginia? Maybe, but that would not be enough to account for such margins. States that her husband was the last to carry? Could be. Upper Plains states (Kansas and northward?) I have yet to see any sign of that.