Thanks for your information! We plan to make this a slow and restful trip in Bulgaria as we will have spent 18 nights in Romania before arriving in Veliko Tarnovo. Our day trips will be short as we want time to get to know each town. We will have a car for the last day in Veliko Tarnovo and may visit Krusuna Waterfalls. Before we get the car we plan to visit Arbanasi by bus. We hope to stop at Etara on the way to Plovdiv and while in Plovdiv we may take a day trip to Assens Fortress and Bachkovo Monastery. From Sofia we'll take a bus trip to Rilski Monastery and Boyana Church. I checked Rhodopi Mountains but it would be a full day round trip from Plovdiv so it won't be possible for us. I checked the sights mentioned in your blog to see if we can fit them in. Looks like we will be driving by Dryanovo Monastery, Etara (already on our plans), and Shipka Monument and Russian Memorial Church. They're now in our plans. Thanks for the link!
As usual, with all the trips we plan we have many more sights and places than we have time to visit. We have just begun to accept that at our ages (75 and 71) we are travelling slower and have to plan accordingly. Taking that into consideration, we're still planning to enjoy the beautiful sights, good food, and great people that we expect to experience.