Do you need an appointment and do they accept card?

You don't need an appointment although highly recommended on the weekends, as it gets very busy. They do accept credit cards.

Yes

It all depends what you need done on the car, if is just a regular wash you need to stop by and wait for your turn, otherwise of you want more things done on your car you do need and appt. Most likely would have to drop it off during the week, weekends are very busy for others things to be done on a car..