If I want to be at MK for rope drop I almost always take the car. Its true that you can't drive directly to the park, you have to park, take the tram to the entrance (ticket area), then take the ferry or monorail (I've heard rumors it will not be in use during your stay) to the actual park entrance)
1- However then you can leave earlier than taking a bus. I am just a very paranoid person and
2- I am always afraid that I will miss it and therefore I leave earlier than the bus would come.
But you certainly can take Disney buses to get there and they will bring you right to the park, no need for ferry rides or monorail (at lease I believe it takes you right to the park, as I've said I never take it to MK). The process would go like this: assuming you are staying at a disney resort, you will get on the bus going to MK at your resort, it will take you there and you will get off at the park. I would recommend checking exactly when the first bus will be coming around and take that one. You will surely get there for rope drop if you take the first bus. If you prefer to drive yourself though you can always do that too. (I love taking the Ferry Across 7 seas lagoon)