JBL parking

Hello everyone, I am taking my sons up to climb Gothics at the end of September. We will be arriving on Sunday and leaving on Tuesday. We have reserved a lean to at JBL just to make things easier on me as far as planning goes. My question is I’m assuming the garden parking lot will be full. What is my alternative to the garden? If you have a reservation at JBL do you get to park in a certain area? I haven’t been to the garden in a couple years so I’m trying to nail down the details. We will not be arriving until the afternoon on Sunday.
Thanks