You should catch the bus to the MK and then walk to the CR. You'll be able to see it from the MK bus stop.
11:15 will be cutting it close, especially if you arrive a few minutes late. It can take about 20-30 minutes to check in, and occassionally even longer if tons of other people arrive right when you do. You should allow about 45 minutes minimum to get to the restaurant, since you don't know when the next MK bus will show up. If you're driving, definitely leave your suitcases in the car rather than unloading them to your room before you go. Personally, I'd get the PS for about 12:30 so that you don't have to rush.