If you're picking up the batte at MCO, just check in online. Go straight to the garage, select your vehicle and leave. As you leave the garage, they will ask to see your reservation and your driver's license. (If you have a second driver, you'l need to show that person's DL also.) That's it. Super easy; barely an inconvenience.
If you're picking it up at the Car Care Center at Disney, call them to arrange a pick up at your resort. They'll shuttle you to the CCC and everything will be taken care of there. You'll still want to do online check-in as it makes everything quicker.
Steve