Just back from Sfakia and further west.
We did the walk, but for a number of reasons completed it in two stretches.
Day one, with full packs, from Niato to Trikoukia and on to Kali Lakki without problems. The path up the gully wasn't, as Jean found, immediately obvious and quite overgrown in places but we forced a way up and met the dots/cairns near the top. That first section could do with marking, if only at the point where the path leaves the shepherds' road, which doesn't seem to be quite where the Anavasi map indicates.
Lennert's reminder about walking west at the top was very helpful though we still managed to get a bit lost at first. During this period I stood on one of those 'rocks which look stable but aren't' and the next second found myself flat on the ground with my rucksack pinning me down. Amazingly I don't have a scratch or bruise to show for it but I did feel a bit shaken up as you can imagine. Anyway, we carried on after a short break and reached Scarfidakia without any problems.
Onwards to Mouri where our real troubles began. We failed dismally to find the route into the gorge and having seen it from Timios Stavros last year were disinclined to take any risks, so with reluctance we retraced our steps and started the long road tramp down to Anopolis. Just before reaching Thesparta we managed to flag down a 4x4 driven by two charming Scots (returning from Pachnes) who willingly gave us a lift down to the village and saved us what would have been a rather footsore hour.
So the following day we walked back up the road to Thesparta to complete the route 'properly'. We found the footpath by leaving the road at Thesparta cistern and followed it without difficulty back down to Anopolis in, as Lennert suggested, 2 hours.
Conclusion - a lovely start and middle but potentially a tedious long tramp at the end if for whatever reason you choose to use the road all the way from Scarfidakia.
PS We'd overnighted at the Panorama Taverna and Rooms at Kares-Askifou. Highly recommended to anyone who fancies walking in that area - very well appointed rooms with a stunning view south across the plateau, good food and a charming family.