As Deb mentioned, there are not any multiday parking passes sold, beyond the "perk" of the Annual Pass allowing free parking (which for some people, the cost of a 10day ticket + 10 days parking makes the AP a better deal for at least 1 person in their party).
When you pay to park, you are given a ticket/receipt which you can then show to the parking attendant if you leave and need to reenter the parking that day. It is also good at all 4 disney parks for that same day.... so let's say you start at AK and then park hop over to MGM, your paid parking from AK is valid over in the MGM lot as well.
Onsite guests, your Disney Resort parking permit also is valid in the theme park lots.