Hi Diana and welcome to the Disney Parks Moms Panel.
You are very wise to plan to get to the Magic Kingdom & Epcot for rope drop during your visit. You will be amazed at just how many attractions you will be able to experience during the first few hours each day before many guests begin to arrive.
On arrival at Walt Disney World, follow the traffic signage for the Magic Kingdom which will actually take you to the Transportation & Ticket Center. The Transportation & Ticket Center is a major transportation hub which also serves as the parking lot for guests driving to the Magic Kingdom.
Once you have parked your car, you will need to use the free tram system to take you from the parking lot to the main hub area. Be sure to make a note of which section you have parked in (or take a photograph) so that you remember where you have parked - this will come in really handy later on when you return to your car. If you will be using a rental car, it may also be worth making a note of the make, model and registration plate number.
Once you have reached the main hub area, you can either take the monorail or ferry boat to the Magic Kingdom. The monorail will most probably be the quickest mode of transport to take unless the ferry boat is about to leave when you get there.
I would suggest that you aim to arrive at the parking lot 45 - 60 minutes prior to park opening to ensure that you have enough time to get to the gates in time for opening. (This allows for travelling time from the parking lot and time to go through security etc.) As a bonus, if you do arrive a little ahead of schedule, you will be able to watch the
Magic Kingdom Welcome Show which is a fantastic way to start your day at the most magical place on earth.
Wishing you a magical holiday filled with memories which will last a lifetime!