A great, tough, experience of 10k or so. 900m height gain. 8 hrs. Very Hard. Prickle Factor Low.
This is not shown on the map but is on the signboards mentioned at the start of Walk 5. It is the only route now graded VH being very steep almost all the way.
Take either of the paths above the water depot. At a signpost on the Picacho path there is a faint but clear path going on but slightly right and turning that way which joins the other path.
Despite the route finding difficulties implied on the signboard upwards there are none. There are fairly regular cairns and/or paint signs & posts.
After 3/400m of height the route flattens out and dog-legs round ravines - the last two very large. At the end of the second (the biggest) dog leg the ridge is reached at a post.
Turn left and go up it. There are cairns now every few metres always on the right of the ridge where there are any difficulties. The ridge itself is an easy scramble almost entirely grade 1 but there may be a few moves of 2, or possibly harder if you don't chose the easiest way.
After another 400m or so of height you turn right just below the signpost to reach La Concha in another 15 mins returning the same way. But, of course, if you're really fit you may want to essay Route 8 instead! See this also for a more detailed description of the descent.