When you encounter a country like Bulgaria where the costs are significantly lower the question is always how to best capitalize on the lower costs. You can either have a less expensive trip or you can invest the savings and see or do more or you can invest the savings in some higher quality services or you can use the savings for a longer trip. No way of looking at it is wrong.
If you go for the savings and take the trains you will get closer to a level of real life, not the real life of every section of society, but of at least one section of society. We had some of our best experiences with the locals on the Septemvri-Dobrinishte narrow gauge line. The people realized that we had no idea how long the ride would be so they started feeding us. The scenery was wonderful, but the people were better. But we did this ride mostly for the experience and the view. Trains are very slow in Bulgaria. A “nice hotel” in a small town in Bulgaria will be less than $40, and I think my guide gets a discount and because there is so little tourism you are among Bulgarians in every hotel.
So let’s say I am going to spend four days in Bulgaria and ride a train each day and that the ride takes one hour longer than the same trip by car, then there is the walk time to the station and the wait time for the train, etc. I guess the car will save me two hours a day x 4 days = almost one full day of sightseeing. Of course that extra day comes at a cost and that cost is roughly the difference of the cost of visiting Bulgaria vs Paris. I am not embarrassed to upgrade when it makes sense, and to say that takes us out of the culture is have the opinion that there are no people of means in Bulgaria or you cant experience the culture unless you do it at the lowest level. Still, we tend to do a little of all the strategies. Save some here, upgrade some there and get to a few more places and stretch the schedule a bit to maximize the investment in money and time. Our trip in a few weeks takes us and some equipment to places that are tough to reach with public transport so this is sort of unique and makes the car/guide worth it.