You mostly described "all over Italy" if you ask me. Rome is amazing to me.. the vatican, the coliseum, thousands of years of history hiding around every corner. If you've never been to Venice, you should see that for a couple days. As for a place to stay for a while, I can't imagine you'd do poorly finding a location that calls to you a bit in Tuscany...
That said, if Italy doesn't turn you on at all ... Spain is incredible to me. We're setting up shop in Barcelona in a couple weeks... last summer, we traveled all over Spain (airbnb's mostly) and were just blown away with Madrid, Sevilla, Granada and many of the beaches. Southern Spain was 35-40 degrees celsius during th summer - I can't imagine it's 'cold' in the fall. Barcelona is really it's own thing.. yes, it's in Spain - but not really a "Spanish City". Cosmopolitan ... and as the capital of Catalonia holding it's own separate culture. (Then again, Grenada/Madrid/Sevilla very much had diverse architecture, history, and culture as well.)
It's been a while since we've been to Italy - so airbnb wasn't a thing yet.
We're living in Costa Rica right now - and specifically decided not to move to Italy long term b/c we heard it was a bit slow moving and we're wanting to get back to a fast moving city life again. That said, I think there are many places there that lend themselves to "nature nearby but not the middle of nowhere".
Hope this helped a bit