Once I was VERY lucky at MK. I stepped out of my car walked 20ft and got on a tram that left right after I got on. I got off the tram, walked to the monorail, walked right onto the express monorail 30 seconds before the doors closed. After that a quick walk to the turnstiles and it took around 15min. But the average is about 25 min or so, and as AP holders we park at MK all the time.