How long does the Rick Steve's self guided tour of Riomaggiore take?
See my same response to your Vernazza question
diane,
I cant recall what RS "self guided tour" consists of, but you can spend as much or as little time as you want touring any of the five towns. Some will take longer than others, according to their size. Each of the towns has one main street, but numerous small side streets and Carroggi (alleys), so the amount of time will depend on how much you want to explore.
If you just want the quick tour in Riomaggiore, walking up the main street and back, and then down the stairs to the harbour and around the corner should only take about 20 minutes. In Vernazza it's only a short walk from the railway platform and then down and around the corner to the harbour. If you're interested in the other towns, Corniglia is very small so it won't take much time to explore. The main street in Manarola goes up hill from the station and also has a small harbour area. Monterosso is the largest town and consists of an "old town" and a "new town" so that will take the most time.