Andre....i can asure you that after 7 years with boats...at least fo me and my wife, sleeping in the boat is better than any 1st class hotel.....ofcourse and to answer and to codprawn our islands have a lot of beaches and coasts that you have almost no fear to sleep inside.....Specially in summer we are discussing for temp of 35-44 celcius, so the night breeze is the best....and the "matresses" are for a very pleasant and relaxing sleep...
also we have a lot of places that you can through anchor,pass across the road and sleep in a nice hotel and from your balcony you can see the boat.
Personally i prefer the boat since i have anything i need....TV,radio/cd,toilet,shower and in the group i belong here in Athens (
www.ofse.gr) we make a lot of travel.....
Wish the distance was smaller so, you could understand that if you live in Greece you have almost anything in a "touch" distance....
from my parking in the sea is 3min...the quicker trip is 40minutes away....
But from hearings i have our seas are not as rough as yours....so it is a hole different mentality in building boats here in Greece from there....That's way for example COBRAs' here are very very "light"....just console and sitting places....
As far as Corinth canal....sorry mate but max speed when passing is 5-6knots....and depending from boat about 60-70euros per passing....