Here's an interesting column from The Politico's Roger Simon from a couple of weeks ago.
He asks an important question:
"[McCain] is certainly the undisputed Republican front-runner. But how does he spend the crucial weeks and months ahead? Does he try to win over Republican conservatives who still distrust him in order to build a strong foundation within his own party? Or does he make overtures to moderate and independent voters, those people who might be the margin of victory in November against the Democratic nominee?"
Yes, good questions. Conservatives will be watching. Specifically, I think he needs to clarify his position on the question of illegal immigration. Polls have consistently shown it's one of the most important issues of the election for the Republican base. McCain's position on it is muddy and amnesty-ish, to say the least. He needs to clarify, for conservatives, EXACTLY what he plans to do on immigration if he becomes president, and to be specific. He has yet to do so. We'll keep watch on this very closely, and see what he does.