Who will receive more votes (nationwide)?

[On Fleek]

It's truly hard to tell iyam.
On the one hand, Jill has gained ballot access in almost every state, whereas McMullin only has gained some in only eleven states (plus many write-in states).
On the other hand, her poll numbers leave a lot to be desired in each state, whereas he is likely to win a state and will probably do well in another.
 

[On Fleek]

To those who (erroneously) voted McMullin over Stein, see Strom Thurmond in the 1948 election for why you're incorrect.

Good point!

[On Fleek]

I am curious, what is the comparison with Thurmond?

In 1948, Thurmond won three states with an overwhelming majority, plus he broke 10% in several other states.
All those states are way bigger than Utah and Idaho, and in addition, McMullin won't reach those high percentages anywhere near.
All in all, Thurmond received 2.41%, only slightly more than the fourth contender in that four-way race:
Progressive Henry Wallace got 2.37%; his best state was New York (only 8.25%), followed by California (4.73%) and North Dakota (3.8%). In some further states he surpassed 3%, but in most he trailed way behind.
Nonetheless, Wallace was almost able to draw level with Thurmond.

McMullin, this year, will win big in Utah and do well in Idaho. However he has gained ballot access in only 11 states. Jill Stein is on the ballot in almost every state. She will win about 2 or 3 per cent in huge states like California and New York. And those are popular vote numbers McMullin cannot catch up with.

Conclusion: Constant dripping wears the stone.