14 days in Europe (Spain (3) / Italy (6) / Greece (5))

I do not have specific recommendations for the type of accommodations you desire.

As for the logistical side given the amount of time you have, the best way from Barcelona to Rome is fly.
If you want to see Venice, Florence and Rome, I suggest you fly from Barcelona to Venice and work your way back to Rome and then fly to Athens.

From there you can boat or fly to an island depending which island you choose. If its Santorini, flying is the better option. If a smaller island, such as Hydra, the boat is the choice

Suggest spending you last night ( or 2 ?) in Athens so you can see the sights and be positioned for the airport

Good luck... I trust you are aware how ambitious your outlined trip is

I am not familiar with Greece, so I will not comment on that. But none of the places you mention in Spain or Italy are small towns. Barcelona and Rome are both big cities, Florence and Venice medium sized cities. There are parts of Venice which can have a small town feel though, it is a matter of getting away from San Marco's Piazza.

In the case of Italy, since you say you do not want to be a typical tourist, I would say ignore Florence and Venice. There are lots of nice and less crowded cities such as Lucca, Ravenna, Padova, Trento, Udine, and many others which are worth visiting, and have many of the things that you are looking for.

Your right, visiting all 3 countries in 14 days is way to ambitious and crazy.

Let me re edit the above and see if it makes more sense then.

I still see 3 countries?? The thing is, a wide-ranging blitz trip makes it harder to get away from the super-touristy cities, because the best transportation tends to be to those places, and it takes extra time to get out to the less-visited towns. With your expressed interest in small towns, you'd do far better to spend all of your time in Italy, or in Spain, or in Austria/Switzerland.

Most of what you asked or post is in conflict. Get a map and put some pins in it so that you get the feel for the distances involved. Second, recognized that any time you change location you lose a half day as a min or more if it involving flying so you need to factor in this lost time. Third, a two night visit is really one day so do you really want to spend one day in Switzerland? or maybe one day in Austria? At best the most you can expect in a two/three night stand is an quick over view of that location. You don't have time for anything else. But in someways that is your objective to get a quick peer so that you can return later for a more extended visit.

Have no idea what you mean by blending in. What do you think it means? What to do you want to accomplish? Really think you should consider limiting yourself to three or maybe four locations with a min amount of travel - two in Spain, two in Italy. Save Switzerland, Austria, Greece for another time.

And finally you might find it helpful to visit you location library for travel guides and especially travel DVDs. The Rick Steves' DVDs are terrific for many of the sites are you are considering.

This may help you with organizing your trip and give guidance on how to approach the task of travel planning

https://www.ricksteves.com/watch-read-listen/read/articles/plan-european-vacation

Arrive Athens (2 nights)
Fly to Santorini (3 nights)
Fly to Rome (3 nights)
Train to Florence (3 nights)
Train to Venice (3 nights)
Depart Venice.

Your stated interests are not jiving with your proposed itineraries. A two night stay is only one day of sightseeing as the day before and after are mostly filled with travel (flights will require travel to/from airports, checkins and security). And one day to see any of the places you mention would be a whirlwind even if you skip half of the main sites. To find places off the beaten path takes some time and adventuring out of the big cities or main neighborhoods of the big cities. Very doable but not with only a day or two in each place.

So, I'd think about one of two things.

1. Do you want to just get a whirlwind overview and taste of a lot of places (as your itinerary proposed) with the idea that you'll go back and spend real quality time in places you liked? You can mostly do that with what your are proposing as long as you fly between major destinations (within Italy you can take the train).

2. Should you skip most of the places on your itinerary and really focus on 1-2 regions that you can settle in, do daytrips to smaller towns and get a full flavor of the place? Any of the cities/countries you list would work for that, and within each country there is plenty to do for 14 days with maybe 2-3 cities/towns to stay in. Then maybe plan to visit the other places your on list in future 10 day trips with the same travel approach.

I won't judge or offer an opinion on either option and no one else really should either since it is your choice on how you really want to travel. But you really do need to decide between the two. From there, we can offer more specific advice on what to do, places to say and what to see.