I'm taking 4 teenage girls to WDW next week and one of the girls is recovering from a foot injury. During a regular day at home, she starts to limp and her foot swells late in the day. I'm guessing that will happen earlier during a Disney day! She will not want to use a wheelchair or ECV until she's already suffering, but I would like to get one in the morning so that we have it when she reaches that point in the day and I don't need to worry about them being sold out. I have no previous experience with either wheelchairs or ECVs in the parks. Are there good places to park them for long periods of the day, but be able to come back for it later? Any advice? Thanks!