This is a demanding walk with little shade, some tricky route finding, heights and a hillwalking style steep descent. You will need boots, 2 litres plus of water, experience and navigational tools. Your reward will include visiting many of the higher summits of SW Lanzarote, huge views to sea, to the Rubicon, to Fuerteventura, hidden places, a secret garden. And there is food and drink at Playa Quemada or Puerto Calero or both for the end.
Start in Femes going uphill to Pico Aceituna mostly on a path but also on some rough ground. If the wind is from the northish you will also get a fine ammonia whiff from a goat farm. If you haven't been here before you will start to experience the odd duality of the ridge walk as you close in on the summit. Sea and desert ridges with dry valleys on the left, East versus the flat lava field of the Rubicon to the West.
From the top with its animal pen there is a view of the main summits of the walk as well as the arid barranco impeded return walk. Ascend Pico Redondo via various informal tracks. As you come down it you will find it rough and boulder strewn. If you find this hard to manage then you will find the much steeper descent from Hacha Grande impossible and you should review your plans. Watch your navigation - you are heading for the head of a track beside another goat farm. This Degollado del Portugues track makes a fascinating zig zag, which you could photograph as an example of repeated form. And you can probably also work the bright red of the SW spur of Atalaya de Femes into a shot as well.
The route up Hacha Grande is easy enough via various tracks. The top has what looks like a trig pillar and, to one side some shade. There are various routes off and the ones to the south are steep and slippery with loose stones. The descent to the col of Degollada Valle Perdomo descends around 340m in around 1000m. This is an average slope of 34% with some parts steeper and requiring light scrambling technique. Once again, don't come this way if you are inexperienced on steep ground - you could for example descend to the coast by backtracking and then taking the ridge between the Barrancos de los Disos and Parrado where there is a rough road.
Pressing on, there is a broad ridge curving left, towards the coast. Following this you end up heading east. This ridge which as of 2013 had a 4x4 track on it has great views of the southern tip of the island and Playa Blanca. Following the track will eventually bring you to the rough drivable track heading to the north. Follow this. As you can see when you get there it isn't possible to readily just walk along the coast because of steep sided gullies so it is necessary to follow a variety of vehicular and walking tracks which add greatly to the distance and somewhat to the ascent. Discovery Walking Guides (DWG) Lanzarote Tour and Trail map shows most of the options. The track published here comes down to the sea at Barranco de la Casita. Note. There is a 4x4 track leading off this N perhaps 800m inland not shown on the DWG map. I didn't take this but it might be a useful option.
At the coast there is a surprising, cool and welcome Secret Garden which you might like to find. Follow tracks to Playa Quemada where you can find refreshments before finishing the walk in another 6k or so.