Small and mid-sized towns in Slovenia, part of Schengen area and eurozone, close to Venice, Zagreb, Ljubljana, Adriatic cost all in two hours drive distance.
Extremely fast broadband even in small towns (up to 200/200 Mbit/s, see www.t-2.net) and LTE/4G (20 Mb/s, 5GB in total, 20 EUR, www.telekom.si). More rustic locations still have good have LTE/4G and ADSL+, some even broadband.
You can get furnished flats starting at 250 EUR/month! But see local real estate site http://www.nepremicnine.net (not in english though) instead of AirBnB to find these. Look for mid-sized towns such as Novo mesto, Koper, Celje, Postojna, Kranj, or even smaller if you’re looking for more rustic variations.