I assume that Theodore Roosevelt would have won, given that he was a much better candidate that Charles Evans Hughes and given the fact that Woodrow Wilson wasn't that popular in 1916.
Here is the map:
Former President Theodore Roosevelt (R-NY)/Senator Hiram Johnson (R-CA): 347 Electoral VotesPresident Woodrow Wilson (D-NJ)/Vice-President Thomas Marshal (D-IN): 184 Electoral VotesI assume that Roosevelt handles World War 1 the same as Wilson, but Roosevelt will most likely still die in early 1919, thus enabling Vice-President Johnson to take over as President. I think that Johnson would have been defeated in 1920 due to the post World War 1 recession, likely by James Cox, who probably would have picked William Gibbs McAdoo or John Davis as his running-mate instead of Franklin Roosevelt.