A F T E R a 14 day RS Greece tour... where would be your go-to island,
to just chill, take in the sites, have great food & wine, and chill?
We're thinking just 3 days or so, then head back to the USA
Naxos !!! Just as “ pretty “ with whitewashed buildings and narrow winding pedestrian paths in town - but a little less touristy and expensive than Mykonos or santorini .
I think Naxos is an excellent suggestion. If you had about a week, I'd recommend Crete, but to go there for only 3 days would be frustrating.
Bear in mind with your three days you need to account for time to get to an island by ferry (return also) but less time to fly and return but flight schedules may not be convenient plus you have to deal with the airport.
If you want to go to a nearby island that has everything a Greek island has to offer then Aegina may work for you.
It's a quick and inexpensive boat ride to get to, has archeological/historic sites, nice main town on the water, seaside villages, abandoned Byzantine Village in the hills, lovely walking/hiking and has a stand of ancient olive groves in the interior plus lots more.
If you can avoid the weekend it would be quieter during the week.
Here's a great website for Aegina for more intimate and less touristy parts of the island. Has nice videos also.