I had a Polish girlfriend who helped. But most anyone under 40 will speak English in the cities.
Warsaw is maybe a day or two and not very interesting. Krakow, Toruń, Gdansk are great. Zakopane is not to be missed. And for fun if you have the time Grudziadz, where my father side came from. Just outside of Gdansk is a wonderful castle made from all brick. Malbork Castle. Not much to see in Eastern Poland but flat farm land. If you enjoy adult beverages Zubrowka is my favorite vodka. When down south in Zakopane, get yourself some smoked string cheese, called ozipek. It is absolutely delicious. The food in the karzmas will guarantee to add a few inches to your belly. Poland is a hidden gem in Europe. The people are a bit stand offish but that comes from growing up under communism. Generally everyone will be friendly and helpful. I wish I were going with you. Have fun.
Zakopane is on my list. I do disagree on Warsaw though. It has changed so much, from the two times I’ve been there (2014 and 2023). It’s become one of my favorite cities. Lots of great restaurants and parks. It’s a lot greener than people think. And they’ve done a lot along the banks of the Wisła.