JimD, I took this RS tour back in 2016. I knew very little about Bulgaria and did not really know what to expect. The country and the tour were unique and memorable, and Stefan was a superb and enthusiastic guide, hope that is still true. I will share one particular suggestion. I don’t know when you will be arriving and if you have any free days in Sofia before the tour. I was there for a few days. Like your Sept 4 start, my tour began on a Sunday, late afternoon, and our Crystal Palace Hotel (?) was quite near the lovely Aleksander Nevski Cathedral. On Sunday morning I moved from my prior B & B to the tour hotel, then went out for more exploring. I had already visited the Cathedral, and knew the tour would be visiting it again. I happened to walk by the side of the Cathedral about 10 am on Sunday, and caught the aroma of incense. I looked inside and realized that Sunday mass was occurring, so I went in. It was one of the most memorable hours of my visit. Very different from religious services of my experience: incense, chanting, lots of candle-lighting, worshippers praying at icons, ornate altar pieces usually closed but all opened up, priests in very ornate garb leading the service, giving communion, etc. Everyone standing, no pews, just a few chairs around the edge for elderly or disabled. I assumed I could not take photos during the service, until there was another visitor with a camera, and a staff member rushed up to him saying: “Sir, you cannot photograph without buying a photo permit!” Photo permit, I thought, so I bought one for 3 dollars or so, and was able to photograph extensively, no one seemed bothered by that at all. Also, there is an excellent “Icon Museum” underneath the Cathedral, with many beautiful Bulgarian icons, ancient to modern. Looking at the front of the Cathedral, the museum entry is to the left, and down a flight of stairs. Just a thought, in case you are interested. Enjoy your upcoming trip, wish I were going with you!