Except Paul is thoroughly acceptable to members of both parties, simply not the party establishment.
Ahaha, what. Polling has shown that is clearly not the case. For one, a horde of Democrats are not going to crossover to Paul. Even Democrats who have a favorable opinion are not going to vote for their own guy (unless he is thoroughly unacceptable, which is very unlikely). And even 1/3rd of Republicans crossing over (and very depressed Republican turnout), should probably give a mainstream Democrat a landslide victory. Plus, independent voters will probably to turn away because there's literally so much dirt on RP. The only reason his favorability is even that high is because nobody in the GOP primary bothered attacking RP because he had no chance of winning.
A popular Democrat (think Bill Clinton circa 1996), has a decent shot of winning every state over RP. Though it's not a certainty. I do suppose it's possible one of those libertarian-leaning, heavily Republican states (Wyoming?) to narrowly vote for Paul.
Polling has shown that this very clearly
is the case. If he is the Republican candidate, Republicans will vote for him, and Democrats who actually care about things like drug policy reform and a sane foreign policy would possibly cross over, and independents certainly would (and you discount independents for no reason whatsoever). Paul could win at least 12 states, bare minimum.