We are nearly at the end of our vacation, and I wanted to thank every one on this forum for all the good advice, and give an update on the trails in the Cinque Terre. We spent 3 nights in Monterosso, and loved the relaxed vibe in the mornings and evenings. We took the train from Pisa (where we dropped off our rental car, stashed our bags at the train station and did the RS walk, had a lovely lunch and confirmed that the tower does lean). There was a no-change train from Pisa to Monterosso (but not the other CT towns). Our hotel (Souvenir, in old town) greeted us with cold beer or wine after the sweaty walk up the hill from the train station, and then we wandered around for a bit before dinner. The next morning we were on the trail by 9:30, hiking from Monterosso to Vernazza in ~1:45 minutes, and then from Vernazza to Corniglia in 1:20. The V-C portion was officially closed but the trail was absolutely fine (very up and down of course, but no obstructions or areas that seemed unsafe). It was stunningly beautiful, and at one point my husband declared this was his favorite experience in all our trips to Europe. After some delicious focaccia in Corniglia, we tried the next section of the trail to Manarola, but found it impassible. There is a 20 - 30 foot chasm on the flat section a little outside Corniglia (past the "beach" access) that has collapsed. It would have been possible to climb up on a stone wall and walk/inch yourself across to the other side, or climb over the wall onto private property and cross that way, but we opted not to do that, though we had heard other travelers discuss making the hike in the other direction. So we backtracked to Corniglia, took the train to Manarola and the boat back to Monterosso. It was a lovely day. We hiked in sneakers which were all you need. I saw people in sandals and flipflops, but I would not recommend that.
BTW, our best meal of the trip so far was at La Cantina di Miky in the new town in Monterosso.