I also agree with forever42, I don't think you're allowing yourself enough time. EVEN if the flight lands on time, your MIL, who you said is slow, she has to deplane (and if near the rear a longer time), has to make her way from the gate, to the monorail to the main terminal, and make her way out to security to greet you. Then you have to walk through the main terminal to the parking area, since you can't wait at the curbs at all at MCO. If MIL is going to have only carry-on items, you might have a shot, but if she's checking bags, you're out of luck making a 5:40PS. I've waited over 45 minutes for bags at MCO many times, they usually aren't very prompt returning bags there. So, you're talking at least 20 minutes from the plane making it to the gate to make it out to the car, and then 30 - 40 minutes to make it to Chef MIckeys. That's the minimum you'll encounter, so having only an hour aand 20 minute window isn't enough and you'll most likely miss your ressie. Either take the later time, or make a PS for another day, you'll be thanking yourself that day when you're not rushing to try make a dinner ressie!!