My first recommendation would be to take a really good look at it in Google Earth.
There is a huge Mountain range (Sierra Julios), that come right down to the shore, halfway between Lobos and Libertad- It is not all beach.
These mountains easily rise to 3500 feet, and do not look easily passable by any motorized vehicle. The shoreline is composed of steep cliffs and jagged rocks for what I estimate was about 5 miles (think Whale Hill or Competition Hill coastlines on steroids)