This is a political marketing question.
Presidential elections are won and lost based on how those who self-identify as "independents" vote. Generally, true Republicans vote red, and true Democrats vote blue, but it's the independents (regardless of their party registration) who can go either way.
Your disagreements on key issues with Republicans like Cheney and McCain can be used to support your claim on the Independent label.
Christie made a lot of political points in this area when he praised Obama for his handling of the hurricane damage in New Jersey. Similarly, how about praising Obama when appropriate? Not too often, but if, for example, he actually makes the right moves at Guantanamo, how about making a big deal out of it?
I realize that this is a post-primary emphasis, but you can't wait until the start of the general to start claiming this, so why not get your claim on the Independent label on the record now? It might make the key difference in the end...
"Know what you know, know what you don't know, and understand and appreciate the distinction."