Clio wrote:Imbros gorge is quite a pleasant, undemanding walk without vertigo inducing heights.
As is the Agia Irini gorge, for which Sougia is the perfect base.
George, I would second Graeme's excellent suggestion, but with a couple of modifications. Agia Irini instead of Samaria, and a bit of a cross-country adventure to start with. As has been said above, roads in the south-west have to go with the (mostly north-south) grain of the mountains or to follow the coastal plains, but you can get from Plakias to Chora Sfakion without a) going up to Vrisses and then down, or b) taking the shadeless, featureless seaside route via Frangocastello.
Head via Mirthios up the Kotsifou gorge, turn left to Kali Sikia, then via Velonado to Arghyroupoli (Lappa). If you don't know the latter, it's a delightful, interesting place well worth a visit in its own right.
But for this longer excursion you pass through, maybe after lunch in the lower village where the food is some of the best in Crete. From there you head to Asi Gonia, birthplace of "Cretan Runner" George Psychoundakis, and then up, up up via Kallikratis to Imbros. This is a wonderful road, probably more so for the passenger, because it ascends really steeply and winds like a corkscrew, with stupendous views.
At Imbros village you can either opt to take a room for a night before heading down to Sfakia in the morning, or to press on to the port and sleep there to be ready for the ferry.
On your return journey you can make a leisurely drive from Sfakia back to Plakias by the coastal route, but bypass boring Frangokastello to stop at one of the lovely beaches below Rodakino which will be a lot less crowded than Elafonissi and to my mind, much nicer.
Clio, do you mean this Kallikratis road ?
http://m.youtube.com/#/watch?v=huAK5_w9 ... uAK5_w9MAo
......and remember this is the road AFTER being widened !
George, that's a good suggestion from Clio, but I disagree about Elafonisi, yes it gets busy, but if you arrive early before the coach tours arrive then its nice and quiet, after 1030 it can get busy, but the best part of the day is after 1600 when most of the tours have left, and sunset at Elafonisi is just jaw dropping even equalling the most famous of Greek sunsets on Santorini. Personally i like swimming at Elafonisi as its shallow with a sandy bottom, one has to go out some distance before your out of your depth.
One other suggestion is to still take the ferry but instead of getting off at Sougia, continue on to Palechora, then explore the beaches and coastal walks between there and Elafonisi.
The clear advantage of taking the ferry is that you avoid having to drive north, then west, then south, spending best part of the day in the car, much nicer to relax and cruise along the south coast.
Just had another idea, take the ferry again and get off at Agia Roumeli and walk up the Samaria gorge as far as you feel comfortable with then either stay at Agia Roumeli for the night or get the afternoon ferry to either Sougia or Paleohora.
Incidentally you do know the E4 walking route goes along the coast from Elafonisi to Paleohora and I don't think there are any places on that section where your vertigo problem would arise.