tennessee is better - although note that it is gore's home state. although note that gore lost it in 2000.
texas is fucked, always has been. and virginia is more of a purple state, really.
if tennessee's numbers are (statistically) the same as the numbers in south carolina, georgia and the other southern states (including arkansas) then it can be safely concluded that the dominant factor in clinton's southern strategy is actually not race, and the media is totally out to lunch. something else will need to be pinpointed (conservative democrats vs liberal democrats).
you also want to look carefully at the numbers in atlanta, where there's a substantial intersection of black and liberal voters. i wish there was a state where the democratic base is both black and liberal - but there isn't. so it's hard to test. atlanta is the closest thing we have in the short term. in the long run, let's see what black voters in chicago and detroit and new york think.
actually, virginia is important to watch, too.
tennessee is your control for race....
but, if sanders does surprisingly well in virginia (which means roughly splitting the delegates), this ideological liberal/conservative split in the democratic party will no doubt become more obvious.
as i think that the split is going to be red/blue, rather than white/black, i'll put down what i think, more explicitly:
1) clinton wins the red states, often by large margins. these are texas, alabama, arkansas, tennessee, !oklahoma and georgia.
2) sanders wins the blue states, often by large margins. these are minnesota, massachusetts, vermont.
3) the purple states will split. these are colorado & virginia.
!polling in oklahoma seems to suggest that sanders is winning that state, which is surprising to me. i'm skeptical. but, keep in mind that oklahoma is so red that "moderates" may identify primarily as republicans, leaving behind a sort of a liberal rump that would benefit sanders. there will, of course, need to be some exceptions to the rule - it will be remarkable if every red state votes for clinton and every blue state votes for sanders.
there's black liberals in virginia, south of dc. keep an eye on them.