Toyota Sienna 8 seat mini van, how do you access to the 3rd row?

Do you fold the middle seat down or the right seat down in order to go to the 3rd row seat? If there are 2 carseats on the left, middle 2nd row seat, can you fold the right seat on the 2nd row and access to the 3rd row seats? Or is it too bersome to walk over that seat? I'm in the market for one and trying to decide if 8 seat Sienna is convenient or not. ( I do like the additional seating ).