IMHO, to maximize your sleep time and park time:
1) Arrive MCO, pick up rental car. Be sure to be in rental car company program so car pick-up is quick. Pay for them to refill tank instead of you buying gas. If you are pre-registered in their program, this should be NO time at all - just the time to walk to the rental car area, pick a car from your assigned area, and a stop at the gate to check out with agent.
2) Drive to a WDW property hotel, check-in, sleep. Ideally, if you have done online check-in and given them a correct arrival time, you should be able to go directly to your room and not even have to go to the main building to "check-in" - use your MB or phone to unlock resort room door.
3) Use car to drive back and forth to all parks and your resort.
4) Drive back to airport earlier enough to catch your flight.
For a quick weekend like this, I would prioritize sleep and park time, not money.