I'm on JD's email list and he said a couple weeks back that early voting in Arizona started in late July, and that he would begin his TV advertising in early July, so you should be seeing something during the next week or two.
Neither he, nor any challenger, would have had the millions McCain had from previous fund raising. JD just topped two million and that is damned good for a challenger in a medium sized state, and he'll probably be able to raise one more million. The Scott Brown thing was a very unusual set of circumstances and few non-incumbents will ever raise the sort of money he raised.
And the two debates are July 16 and 17, so JD's campaign should be very evident from then until August 24.
Meanwhile, McCain is doing permanent damage that JD won’t be able to fix later. I understand the hanging on to the money part, but the damage being done in June will be impossible to fix with any amount of money spent in July.