You might choose to stay at one location over another and miss out on something wonderful that might only have been a 10 min drive from where you're staying.
I do agree with spiritus on this one, but at the same time I do not think you need to book any accommodation before you travel, esp in April, before the tourist season.
It can be much more fun and exciting to just go somewhere and see what you find. I've done this in Poland myself, and without a car, which makes it much more a case of "winging it" because, if I didn't find anywhere, I didn't have a car to take me someplace else or to sleep in!
See my story of arriving in Poznan off the train from London.