Mickey and Friends parking structure is usually the most convenient--with a constant shuttle. In the summer it can fill up by 11, so you should be fine if you get there early. The other parking lots include Pumba on Disney way, they have a bus shuttle service (not as constant as Mickey); Toy Story lot, never parked there and I don't know if there's a shuttle; or if it's really busy, Disney will have you park in one of the hotel parking lots, and there's no shuttle and you have to walk down DTD--not my favorite at night with a tired child. The only inconvenience with shuttles is you have to remove your child from a stroller. You didn't say how old your child is or whether he/she would be in a stroller, but when my children were young enough for strollers, I would HATE having to take my sleeping child out of the stroller, and fold up the stroller, to board the shuttle.