As the PPs have said, there is no charge to self park at the resorts. You can also valet park ($15/day plus tip) if you wanted to.
For CR, when you approach the toll plaza for MK (assuming you're coming from somewhere outside of MK or the MK resorts), be in the right lanes. Otherwise, you'll end up having to cross all of lanes to avoid being funneled to the MK parking lot.