Can't comment on the train trip from CT to Venice, but let me try and describe the magical world of Cinque Terre. No ... sorry ... no words can describe how beautiful it is.
We stayed in Vernazza because it is said to be the most pitoresque of the five of them. We had wonderful accommodations at LaMala. Our first hike was along the Via dell'Amore and it was an easy walk. We took the train to Riomaggiore and then hiked backwards to Manarola. This was an easy walk - and believe me, we are not hikers at all. We then took the ferry back to Vernazza that afternoon. Encouraged by the ease with which we took this first walk, we were determined to do them all.
The next day we took the train to Monterosso and attempted the hike back to Vernazza. This is where our lack of hiking experience really showed up. It is a VERY difficult trek - up hill and down, hundreds of stairs, tiny paths - we didn't make it. We went about 1/3 of the way and decided it was a little much for us in the afternoon 104 degree sun. We simply went back to Monterosso, had another afternoon glass of wine, and then took the train back to Vernazza for a swim.
Undeterred, the following day we took the train to Manarola and did the hike from Manarola to the train station below Corniglia. This was not overly difficult - a bit more up and down than the Via dell'Amore, but nothing like the Monterosso path. We then took the shuttle up to Corniglia and explored. We felt good, so we decided to walk then from Corniglia back to Vernazza. This, too, is a very challenging hike. The saving grace is the restaurant which is about 2/3 back towards Vernazza. Cold beer has never tasted so good! We took about 2 hours for this walk - longer than is posted, but we walked, chatted with people along the way, rested, took photos and enjoyed the beautiful, breathtaking scenery.
I've travelled a little bit, but really have never seen scenery like this before. Enjoy every minute!