While Obama did much better than Gore or Kerry -- by winning the election, for instance -- it apparently remains the case that Republicans can percolate countywise across the country, i.e. traverse it from coast to coast without passing through a Democratic county. (Source.) Apparently because I don't know if there are roads that stay entirely on the red percolating path. (Otherwise one might have to drive one's SUV through the backyards of bitter gun-clingers.) However, we're just two or three counties away from having a wall of blue down the west coast.
The Congressional-district-wise map is even more tantalizing... one district in eastern Tennessee is all that stands between us and total victory. If I were the DCCC I would pour all my money into winning that seat. (I've marked it in yellow.) Note that percolating into the Gulf does not count.