First, in order to park at Fort Custer, your vehicle needs a Michigan parks recreation pass. This was the extra $11 you had the option to pay when renewing your registration. If you don't remember, you can check your registration or license plate sticker. The sticker will have a "P" on it as shown in the image below.
Anyone can drive into the park to drop off or pick up athletes without a pass, or you can buy one at the entrance that day (they are $11, good for a year, and work for all state parks). I will be driving from the middle school and can take a few athletes, and I know some students have the pass on their cars. Please make arrangements in advance!