Anyone have experience renting car seats? We will be going to Cape Cod and Boston this summer. I'd bring ours, but we are turning in the rental car once we get into Boston. The idea of lugging/wheeling 2 car seats, suitcases and a stroller to the train/airport is a bit overwhelming. I'm considering renting carseats and a pack n play but am hesitant due to safety concerns. I found the carseats to be cheaper (and Britax) through a private rental company vs the car rental agency. Any advice or suggestions would be appreciated.