They really have two major options for gettable voters:
1. The Midwestern Strategy- this would be a narrow R win with these voters
This would be the long-sought-after Republican breakthrough in the Rust Belt. I'm not sure if MI or MN would be the last non-IL holdout, but I went with MI because it has a more diverse electorate.
2. The Minority+Yuppie Strategy
This basically represents a return to the Bush coalition, but it is accomplished by being less socially conservative on the whole.
Prior to the election, the GOP seemed to be concentrating on the first strategy. Romney was trying hard for this in 2012 and he basically ignored/took for granted the Bush-Obama states in the process. After they got burned with that plan, they seem to be shifting gears back toward the 2nd option.