I am an older person travelling with my 19 year old granddaughter. We want to do some hiking along the trails and would like any hints about that. Also I was thinking of taking collapsible trekking poles for me but wonder if there would be a place in Vernazza to rent them as well as obtaining good maps.
The paths are exceedingly well marked in CT (most trails I've encountered in Italy have been well maintained and signed). I'd just take a look at the park website for choosing a trail: http://www.parconazionale5terre.it/Esentieri-outdoor.php
There are some steep ascents with steps, but slow and steady wins the race.
Don't know about poles, but if you are checking a bag I see no reason to not just take them. I've read of others buying them in country and then just leaving them.
This sports store in Vernazza has trekking poles. I don't know if they are only for sale or also for rent. So no need to carry them from home.
I used wood sticks I found along the trail last time I went (maybe 15 years ago), and they worked fine. We are becoming too addicted to "expensive gadgets" nowadays.
No needs for maps. It's impossible to get lost. Wherever you are you can see the Ligurian Sea on one side and a steep mountain hill on the other side. Just avoid falling down to the sea, or going up higher in the mountain, and you'll be fine. The trails are easy to follow. It can be strenuous in certain uphill stretches, so take it easy.