Some people may not know that there's ferry between the last two villages. (Venazza and Monterosso) Take that if you are tired of hiking. I enjoyed the boat a lot since the view is different from mountains. BTW, the beaches at Monterosso are so nice so you may want to get there early and spend more time there!
Get out and visit the quarries at Carrara, that is where Michelangelo got his marble for his wonderful sculptures. It is a steep climb up into the hills bu you can really see how white the marble is and how big the industry still is.
Not far from Pisa is the lovely city of LUCCA.
Walled city - you can cycle/walk around the walls for a good general view. See much more in the travelogue on my Lucca page.