This proposition of mine, based on your specific wishes, is a good example in my opinion of sustainable tourism: a bike tour to the painted monasteries of Bucovina (Northern Moldavia). We can put together sport,culture and even some joy of life, tasting a glass of wine (and even drinking it with the right food)

All these monasteries seem to be perfectly set in the environment

The Romanian painted monasteries aimed to bring the faith nearer to the people. They are unique and their original secret vegetable paintings still hold on today.
These painted monasteries have been made in majority by the Moldavian ruler Stephen the Great, called by the Pope from that time (1457-1504)  ” an athlete of Christianity”.  He fought against the Turks, being also very cruel! Actually he lives even today in the local legends!
To reach all the above mentioned monasteries you will notice the wonderful wooden hills, and the villages where the ancient traditions still play an important role. Nowadays these monasteries are UNESCO protected, and represent one of the most important attractions of a visit in Romania.

They are compact and easy reachable during a short vacations of 4 days, as follows:
The Romanian painted monasteries  by bike

Day 1 Arrival in Bucharest, transfer in Suceava by bus. Good *** hotels for  the next 3 days, breakfast included, any other meals will be extra charged.

Day 2 50 km bike ride with visits in the monasteries of Dragomirna and Putna. Bikes and entrance fees in organizer’s charge.

Day 3 50 km bike ride with visits in the monasteries of Sucevita, Moldovita and Voronet

Day 4 Transfer by bus to the Bucharest airport with city breaks in Bacau and Focsani (lunch possibilities, extra charge)

Final prize  is 350 $ comprising hotel, bikes and logistics, guiding, entrance fees. The prize does not comprise any other meals and plane tickets!