I might be mis-understanding your question, but you can't get a head start before the rope drops.
My oldest DD and I were in MK 2 years ago at rope drop. The park turnstiles open before the official opening time, which allowed people to get into the Main Street area. There were ropes at the entrance to each land. DD and I went to Fantasyland; the rope was just beyond the entrance to Cinderella's Royal Table (at the Fantasyland side of the castle opening). We saw one family who came out of the door from Cinderella's into the Fantasyland area beyond the rope (one door was in front of the rope and one door waas behind the rope). The kids were running ahead and yelling about what rides they would go on before the rope drop. One of the parents made a comment about what a good idea they had to get a head start. They only got a little way before a CM sent them back to our side of the rope to wait for the rope drop (and they ended up behind a lot of people alredy waiting for the rope to drop). We spent the next 15 minutes listening to the kids whining about being hungry and the parents arguing about having rushed thru breakfast to get a head start that they didn't get.
So, if you want breakfast before the rope drop, you can get that, but you won't get any head start on other guests.