Over the next 50 years, I really don't see the colored states moving, as long as the GOP spouts some basic form of conservatism (be that pro-business policies, nationalism, religious conservatism, libertarianism ... doesn't matter) and the Democrats spout some basic form of "the left" (be that economic populism, cultural tolerance and multiculturalism, SJW-type stuff ... doesn't matter, either). Everything else is conceivable to move from being safe depending on the parties' focuses. Now, I think that some of those moves (see: Alabama or New Jersey) would take a VERY long time, but there's a way I could rationalize it. The colored in states (or the versions of those states that now exist, at least) have been on the train, so to speak, through whatever their parties threw at them, in one way or another.
These are not the states that I think are most likely to stay ... for example, I can't see a future where Tennessee isn't SOLIDLY Republican, and I doubt VERY, VERY much that New Mexico goes Republican anytime soon, but there is at least a path I can see. States like North Dakota and Maryland are happy with their locally dominant parties, and they haven't had wild swings.
As for the idea of the OP, I will echo that I don't think there's a cohesive strategy. I think Trump wanted to get elected, got enough momentum to win the primary and knew that his path to the White House was picking off Rust Belt Obama states, and he (barely) got it done. The GOP realized it was him or President Hillary, and most fell in line. I really believe that post-Trump, the GOP's future is up for grabs, 100%. There is no clear direction after this, and there will be a big-time fight for the party's soul. Republicans who opposed Trump know that, and they're not about to ditch the party.
