I spent six days walking it in September: first a day inland walking north, then west to the coast, then four days south. It was an amazing walk: beautiful scenery, lovely people, great food. Even though we spent four days walking almost entirely along the cliff tops, there was plenty of variation. The trail is well-marked, with only one exception that I recall (a car park was being constructed).
Inland you need to take enough water: we had 5.5 litres between the two of us, and drank it all (then again, it was 31°C). Along the coast there are plenty of villages and bars.
On the whole the walking wasn't very difficult, but you spend a lot of time going through soft sand -- not just on the beach, but also along the tops of the cliffs. Yes, the Rota Vicentina manages to combine rock cliffs with soft sand dunes. We had hiking poles, and that made a huge difference: just point them behind you and shove yourself along. Once you get a steady rhythm going it's much easier. I'd recommend using snow baskets to maximise the surface area.
Let me know if there's anything specific you're curious about.
