I know how exhausting it is to fly to Greece from the west coast. Our last trip was 27 hours.
Just curious are you planning any other destinations in Greece. Many of us recommend you get to your first island immediately on arrival in Athens. Jet lagged in Athens is no fun at all. Jet lagged on an island is much better experience.
Getting to your hotel. There is an express bus to Syntagma square however you will have to walk to the hotel with bags. Maybe 6 to 8 euros
You can also take the Metro into central Athens with several different stops so the walk to the hotel may be closer. The metro is safe but is infested with pickpockets. They like jet lagged tourists. 14 to 16 euros for two people if I am remembering correctly.
Best bet would be to take a taxi. It s a fixed rate of 38 euros during the day into the evening. Late night and early morning its a higher rate. The taxi will take you directly to your hotel.
Last October we had an early flight and had to get a taxi at 5am. I wasn't too keen on hoping a regular taxi would work that early particularly as we were at a vacation rental. At a hotel you can rely on them to call a taxi that they have experience with.
We went on line and booked a private transfer. At 4:55 we stepped out our front door and there was the cab waiting. It was a big black Mercedes with an English speaking driver. Same rate as the taxi.