Walking in Greece and Turkey Ports

My husband and I are interested in taking a Greek Isles cruise which visits Mykonos, Santorini, Ephesus, Athens and Katakolon.

I have a slight disability which causes bad balance and not a ton of strength on my right side. I know that private tours would be the best bet, but I have a couple questions.

• The distance between the tender and the pier at the ports...how deep/steep is it? I was surprised in Montenegro and Split last year which caused some strategic planning, and even then it was difficult.
  
• My husband is my human "railing" at times. That being said, are there many sights that even this would be difficult in?
  

In Katakolon we docked in the town, there were horse rides close to the pier, also an interesting museum of inventions.

Mykonos can be challenging, uneven surfaces.