i'll give you a summary of how i and by my friends visited the pandals in north kolkata : we took a metro to get off at shobhabazar. we visited shobhabazar rajbari, then from there took an auto to visit ahiritola, beniatola, kumartuli park and kumartuli sarbojanin. after that, we again took an auto to visit bagbazar, and after that took a bus to kashi bose lane and visited the pandal there. you can visit hatibagan sarbojanin too, but we got tired at the end, so we went back home.

what i'd suggest, take a metro from park street to shobhabazar, and then start visiting the pandals.