Currently the Lovers walk from Riomaggiore to Manarola is closed.  For experienced hikers there is a new route 531 which follows an inland route through vineyards and over the hills. It is signposted from the castello - follow via tra castello to the 531 signpost.  After this the next signpost is two thirds of the way up the hill : so don't set off unless you have a excellent sense of direction, and a good map/GPS device.

 Caution : this route is for experienced fit hikers only, wear appropriate footwear and note it is very steep. In places it is twice as steep as an ordinary flight of stairs. 

 It's a great walk.