Bryan, in regards to the CT (Portofino is outside of the formal boundaries of that region)....
There are no "cities" in the park: there are five villages and they are small (Monterosso) to tiny (Corniglia). As previously noted, 2 of the four segments of the most-traveled route between them - the SVA2/Blue Trail/Sentiero Azzurro - are closed and will remain so this season. The legs between Monterosso>Vernazza> Corniglia are open but, like any of the trails in the park, can close at any time for weather or damage. This map shows you where the open trails are and provides descriptions of each:
http://www.parconazionale5terre.it/Esentieri-outdoor.php
Black lines are closed trails; orange lines are open-but-skilled trails; green lines are open trails. The green line trails may or may not be "easier" depending on length and physical fitness.
You do need park passes to hike any open segment of the SVA2, and combo 1-day trail +unlimited 2nd-class rail passes within the region are (La Spezia, Levanto, + the 5 CT villages in between) are available as well:
http://www.parconazionale5terre.it/Ecinque-terre-card.php
We hiked the SVA2 back when only the leg between Corniglia and Manarola was closed, as it has been for many years now. Sections involve a lot of steep, shallow steps both up and down, and I'll say it's not for couch potatoes, anyone with knee or hip problems, compromised breathing, or with very small children. You are also required to have adequate footwear: no flimsy flipflops or non-hiking sandals. That said, you also do not need hiking boots: we did it in just the sturdy, closed-toes shoes with good tread (good tread is a MUST for Italy for dealing with slippery surfaces!) we wore for the rest of our trip. I'd expect it to be a busy, conga line of hikers during peak hours.
If they might be useful, I'd included a couple of youtube videos of both open sections in this thread for someone who was afraid of heights:
https://community.ricksteves.com/travel-forum/italy/steep-cliffs-on-hikes-in-cinque-terre