I was told by a CM that there are toddler potties at the Babycenter at MK, but we didn't need them at the time, so I didn't check.
However, we have a foldable potty seat and those things ROCK! Last time, Julie pinched her butt on it ... but it was her own fault, she was trying to stand up on it being silly.
I also saw disposable liners that stick to the potty, but cover them enough so their hands don't touch the potty. I might bring that this time along since it will just be Julie and I ... and I won't have anyone to pass the bag along too.
I agree with the post its ... they are GREAT for the potty sensor. I slip one over, put the cover on, let Julie do her business ... and ten minutes later we're able to leave the bathroom. I swear we spend more time in the potty than we do on the rides.