Those who oppose Trump fall, basically speaking, into two categories - those who view him as unprincipled/a changeling/just another liberal, and those who view him as, well, a wackobird. I'm mainly in the latter camp. And for someone with my kinds of concerns, I can't think of a better choice for Trump's VP than Jim Webb.
Webb may have ideological flaws (as noted earlier, he's pro-choice), but he's the one choice that telegraphs Trump's seriousness and humility to seek the kind of counsel he'll need as President. Webb's resume is varied and actually quite amazing, he'd have cross-party appeal, and he brings heft to the one area - foreign policy - where Trump's personality scares people the most.
Webb also, like Trump and the rest of us, has a problem with Hillary - he said a few months ago he wouldn't vote for Clinton but might for Trump.
Free advice from a confirmed #NeverTrump is worth the price paid, but if Trump were to ask me, his best veep option is Jim Webb.