Starting from your hotel in Skopje, traveling to Skopje with visit of Rila Monastery for about 2 hours, after that break for coffee or lunch. After that continue your trip to Sofia and drop off of your address or your hotel accommodation.
Rila Monastery is definitely a must-see if you are a tourist with a free day in Sofia. The arcaded balconies, the unique frescoes a work of one of the most famous Bulgarian Revival Period painters, the gilded iconostasis, the fabulous mountain views and the unique combination of them all makes the visit to the monastery extraordinary and memorable one. You will have at least two full hours of free time at the Rila Monastery to explore the most visited UNESCO site in Bulgaria, enter the main church and take photos of the narthexs gallery, admire the exhibits in the History Museum of the Monastery, try the tasty "mekitsi" (Bulgarian donnuts) with delicious buffalos yogurt (local specialty) or even have a short walk in the area;