Indeed. Poland and its various bits have a very complicated history, involving Lithuania, Austrian-Hungarian Empire and then Nazi Germany, Russians and the Soviet Union.Lots to see - it is a big country. Read up on the history of Poland - it will give you a much better understanding of the differences and impact of history around the country.
Most roads in the SW we drove on were great. A couple were appaling, the worst that I have driven on in Europe.A beautiful country, with some equally beautiful people and history. I worked there many years ago, travelling in SW Poland in a VW Campervan. Some of the minor roads were terribly potholed, others were still cobbled. It may have changed, but as stated above, please do some careful route planning, or check out road conditions on Google maps, if covered or available. Good luck!