Don't sweat it you will be fine. The cast members will get you in just fine.
We have had breakfast/ early reservations before even an hour prior to the park opening. Yes, some restaurants are open and serving even before rope drop. We show our reservations to the cast members who are usually off to one side or as you get thru security and they point you to where you can get in. They make arrangements for those with early reservations. In your case being 10 min after opening, you just need to get there soon enough, but I would ask a cast member for an early access. Does that day have early magic hours? It's only a 5 minute walk from the front gate. They will hold your reservations for a while. No worries about that. You will be good regardless of how you get there as long as you plan enough time to start with. You'll have a great time.
We live close to Disney, so will drive over. Thx!
Where are you staying? If staying at a Disney hotel/lodging, you should have early access to the parks. If not, you should arrive at the Magic Kingdom gate early. The Crystal Palace is close to the gate so it wont take long to get there once you get through security.
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