Favourites of mine in Sofia were the Happy Bar & Grill and a cheap wee back street bar called the Up and Down.
In Skopje, go across the Old Stone Bridge to the Old Bazaar area for food & drink.
We drove from Sofia to Skopje (mainly so we could also visit Ohrid), and it was an adventure in itself. The hire company provided the right border papers & insurance for Macedonia. I needed an international driving permit, but don't see them on the country list any more.
August there will be a furnace.