Jean --- someone from Hungary, who can get to Greece in a few hours, for a few hundre €€€ will have a different outlook, certainly worthwhile, but not as applicable to someone who comes halfway around the world. I'll give you my (somewhat dated) info based on a very interesting trip to the East Aegean about a dozen years ago...
SAMOS -- it's an ideal "springboard" to see several islands... we stayed at Hotel Pythagoras, which is n Vathy, about 300 meters north of the ferry pier, riht on the water. Family-run place, with a street-floor cafe. Super-handy for Samos Visit. First, theother "stops"
• EPHESUS - I think a day trip is great, if you can find the excursion. The travel agency right at the pier fixed it up for us ... in season there are ferries at 7:30 AM or so they may be going from the other town ... Pythagoras, I forget. if you stay more than 1 day there's a bunch of paperwork, because then u are officially visiting in Turkey -- for 1 day, they just hold your passport and you pay I think 25E or so as "entry fee." You can do it without a "tour". Just take the ferry & get a taxi from the port to the ancient site (do homework beforehand in guidebooks &online so u know what you are seeing). Often a "tour" will drag you offsite to go to rug shops. Ugh Here is the Turky-Travel website: https://turkeytravelplanner.com/trans/index.html Other important plan-links:
Ephesus Ferry boking - http://www.feribot.net/index.php
Ephesus Map - http://www.planetware.com/map/ephesus-map-tr-eph.htm
http://www.planetware.com/tourist-attractions-/ephesus-tr-iz-ep.htm
Temple of Artemis - http://en.wikipedia.org/wiki/Temple_of_Artemis#Ephesian_Artemis
• CHIOS - Magic!! Requires 1 overnight! Stay n port town... rent car & go to "mastic Villages" and amazing deserted monastery scene of 1826 Turkish Massacre (25K killed in one day; women & children taken back to turkey into slavery) Mastic villages unforgettable, beautiful beaches, here's a good Chios trip report = https://www.tripadvisor.com/ShowTopic-g189476-i2411-k10944884-Chios_Trip_Report_Sept_30_Oct_10_2017-Chios_Northeast_Aegean_Islands.html NOTE: only 2-3 ferries per week,and often leave/return iin middle of night... still, totally worth it!!!
• PATMOS - there are 1-day excursions here too... best part is vista of St John monasteryon approach, but actual visit to it, meh. If you are rushed, skip it.
. SAMOS --- a Great Island! too much to say & I'm off to a meeeting... more later.