If I don't want to do the tour is there a place to park and just walk through? I want to see the changing of the guard and the Kennedy graves

You do not have to do the tour. You can walk to the Kennedy grave and to see the changing of the guard. You may still need to pay a fee to walk through the cemetery.

There is a paid parking garage at the entrance. Once you enter through security, you can walk through. There is no fee to walk through the cemetery