During a holiday stay on Madeira I decided to try the crossing of the island. I started at sunrise in Ribeira Brava at the Cafe on the beach across the parking lot and went up along the village. The levada was easy to run but the track afterwards was sometimes heavily overgrown so I had to stick to a dirt road and couldn't use the hiking trails shown on Komoot. This may be due to the season as I went in the winter months. The plateau was quite windy but as soon I reached the downhill to Sao Vicente the sun came out and it was a really nice trip.
One can go back to Ribeira Brava with the public bus as I did. It takes about an hour and one should check the departure times before. I had to wait two hours for it. Mind you, it could be worse then sitting on an empty beach watching the waves.