I live and work in Plovdiv. No time soon will I visit Bucharest, but I will have that in mind when time comes eventually. I am free for a few hours on the 19th of August and the entire two days on 20th and 21st of August and I can give you a little tour around whenever you like.
Stara Zagora is a town approx. 100km east of Plovdiv. It's easily accessible by train and it's rather cheap non the less (best choice for transportation to that destination for me though). Last time I went there, that was somewhere around mid November of 2014, the were a lot of Skoda Solaris 26 Tr's and a few remaining Ziu's and Skoda 14 Tr's, quite the number of Mercedes-Benz O405's and Kassbohrer Setra 200 series's. We can go there if you'd like.
In Plovdiv, we don't have any form of electric transport, but the old power grid still remains. There are, now former and abandoned, Surer GT560 and VanHool AG280T trolleys finding rest in and old depot in the northeren part of the city. There is also an abandoned Skoda 14Tr in another depot, this time in the eastern end of the city. Near it, there is now another Skoda 14Tr that is meant to be a driving lesson's trolley. It was brought here from Pazardjik, as far as I know, in exchange for our Skoda 9Tr.
Last time I forgot to mention that we have quite the number of VDL Berkhof Ambassador 200, lots of IVECO's Irisbus Citelis 12M CNG, Temsa's Metropol and MD9 LE model, a few Mercedes-Benz Citaro's and MAN SL283's. There is also a large number of Kassbohrer Setra 200 and 300 series's that service intercity routes. Occasionally there could be spotted other different models from the Mercedes-Benz, VDL, Vanhool, MAN, Neoplan brands also servicing intercity routes.