Greece Recommendations

Definitely need to rent a quad for Mykonos.. island or not, the nicer things to do (since you're also going with a girlfriend) are usually far apart.. one thing you will rarely see mentioned, but I've gone there for the sunrise on no sleep after CAVO is Panormos Beach which is on the other side of the island.. wow.. nicest view and beach for sure in Mykonos / attracts a much more affluent clientele as well.. none of that cheesy IG stuff, also don't underestimate the ORNOS area, more family, less tourist-trappy, very good sit down restaurants.. it's like where the Greek people both from Greece and the Diaspora like to settle at if they visit Mykonos I'd say. Again, you're with the girlfriend, so it's up to you but you got from South Beach Clevelander's (Tropicana) to Alemagou Beach Bar (think of your trendy beach bar / day spot anywhere in the world). I find all the new clout flex restaurants pretty trash tbh, so can't guide you there. If not, if you're splurging on accomodations and other things, one thing to know about Greece is a couple gyro pitas will be both cheap and fill you up anytime any place..

Santorini - the whole point is to do the "Google" and "Instagram" cheesy things, so just go on IG search "Santorini" and see all the photos that come up and see what you want to do..

Athens - you need to stay in Glyfada unless you want a super local vibe, then by all means book in the city, but definitely nothing to be proud of these days.. the people much like everywhere else are at their tipping points, so I imagine things could be a bit difficult for tourists not traveling with a Greek/someone who speaks Greek, in terms of being fleeced, maybe mugged, tourist traps, etc. classic European stuff.. but of course need to do a day trip and visit the Acropolis/Parthenon and the museum, and then you can do lunch in Monastiraki Square, and if you're staying the whole day in the city then for sure one of the rooftop terraces that have the Acropolis view (A for Athens for instance)

-- all in all, I'm guessing it's your first time / younger of age, but yes those islands are definitely the most cliche and nowhere near the nicest or an accurate portrayal of getting that "Greek hospitality" since they're both pretty much rackets at this point for a handful of people / corporations / families to wildly profit off lol.. if you have time then Naxos, Paros, Tinos, Milos, are great islands near your itinerary.. if not Crete of course, Rhodes, Karpathos (super lowkey, but beautiful and where like 99% of all the Greek diners in NYC/NJ and along the interstate originate from lol) and you can hop over quickly and do the Eastern Turkey side (which will remind you of Greece, but on a budget since culture-wise and things to see, architecture, etc. is mainly from when there was Greek city states in the area.

-- then West Coast you have really super contenders.. Zakynthos, Cephalonia, Lefkada (Skorpios Island is right there which was Onassis' island that I think has been leased to some Russian Oligarch), Corfu + again Greece on a budget isn't far (Albania - gorgeous as well)

-- if you want to play with big Daddy MF and HF billionaires then Spetses, Hydra, Porto Heli, area (Greece's version of St-Barths)