Now that the ancient footpath Acquacarbone has been cleared, several new  routes for walking from Sant'Agata to Massa Lubrense (or to Sorrento) have become possible. This is my favourite since it has a real Italian feel to it.
In less than 5 kms and with a minimum elevation change (280m of which just 30m up), this itinerary will take you away from the tourists and through some authentic Italian countryside: passing through woods, past vegetable gardens, vineyards and of course orange and lemon groves.
With your back to the church in Sant’Agata walk down the Corso  and take the first turning to the left along via Termini. Turn left  after the restaurant Mimì, just before the arch, and then left again in front of  Hotel Iaccarino. After a couple of hundred metres in the shade of the walnut trees, turn right up a slight slope and you will soon come out into open countryside walking along the panoramic dirt-track of via Olivella. Follow this, first on the level and then slightly downhill, until you come back onto asphalt.  Continue for a couple of dozen metres in the same direction and immediately after the first bend, (where there is a steep descent leading to the main road Nastro Verde), go left onto  the narrow dirt track, via Acquacarbone and through a chestnut coppice.
Once out of the wood there is a short, partially paved stretch downhill  before you turn left onto another dirt track with a wire mesh fence to your right, through which you can see a small vineyard.

About 200 metres after crossing a tiny rivulet, you come back onto a paved surface. Keep straight on until you come to the main Nastro Verde road (ss 145 Sorrentina, between Sant’Agata and Sorrento) which at that point you can easily cross.

Walk down the road for roughly a hundred metres before descending  the cement steps straight after Hotel Il Nido. At the bottom you will find a pleasant, gently sloping  path taking you through  olive and lemon groves and down a lane to the church of S. Atanasio in Priora. From here if you want to go to Sorrento proceed down the path to the left of the church and under the arch or follow the road to the right; for Massa, go left and walk for about 300m along  the road via Crocevia.  Just a few metres before the junction with Nastro Verde, go straight on across the little clearing which will bring you to the top of  the bend.
Here you need to be very careful crossing the road which can be busy. At this point there are three lanes in front of you. You need the one furthest to the left and going uphill,  via San Giuseppe. If you miss the name, just follow the signs to Villa Eliana and once you come to its entrance, follow the lane to the right. A few metres later you will pass the chapel of San Giuseppe.  Continue along this lane to its end walking along paved stretches alternating with a rough track. You will now come to a narrow road (via Bagnulo); go to the left and   once again you will be walking past gardens, trees and vegetable plots. You will go   under an arch and after a few metres turn right and follow the narrow, bending road which will soon bring you to the main Massa - Turro road (the road to Sant’Agata) marked by an impressive pine tree. Cross the road and walk along Via Vecchia before taking the turning to the left (via Maldacea) which will bring you into the heart of the old hamlet of Mortora, 200 m from the square of  Massa Lubrense. Go down to the right along via Mortella to Rachione, and on into the centre of Massa Lubrense. Do take time to visit the ancient Cerriglio fountain.

Video and map courtesy of Giovanni Visetti who also devised this itinerary.