I agree with Bigbulg. I have done this a few times when not sure and it has saved time and frustration (not just in Bulgaria) . It is a lot to take in when you first arrive - which route, reading the signs and driving at the same time.
It costs very little to get a taxi to lead you to the road you want. You could also ask the hire car company to do this - twice now I have had cars delivered to my hotel in Sofia and the car hire people have kindly driven in front of me and showed me the way to go. When they know I am on the correct road they just signal me to carry on and go off with a cheery wave - that is Sikon Car Hire. I have also stopped in Plovdiv as I learned on this site that the Hebros Hotel is hard to find - how right they were! Even the taxi had problems but he radioed in for directions and it was much easier following him through the twists and turns of the old town. When returning to Sofia, sometimes I find it easy and sometimes I get lost
- it depends where I am coming from. I try for a while to find my way around but if not, I just pull in at a convenient taxi and give them a few bob to lead me where I want to go.