Hi there, Leah. Thanks for stopping by the Disney Parks Moms Panel with your question. I personally love doing multiple parks in one day. On my last trip, a few days ago, my daughter picked to do all four parks in one day, so fun!
To get from
Epcot to
Magic Kingdom Park is really very easy and won't take up too much of that precious park time. You will want to use the
monorail system, which is like an attraction in itself. When my daughter was younger, no trip was complete until we took a monorail ride. From Epcot, you'll board the monorail right outside of the entrance and ride it to the Transportation and Ticket Center. There, you'll need to hop off and transfer to the monorail line that takes you to Magic Kingdom Park. The monorail lines are right next to each other and there is plenty of signage, you won't have a problem finding it. Typically, it takes about 45 minutes to make this journey.
Since you are spending the evening at Magic Kingdom Park, can I make a suggestion? You will not want to miss
Happily Ever After, the firework show, when you're there. Lights, lasers, special effects, music and not to mention fireworks puts this at the top of my must do list every time I'm there. I hope you'll get to experience it as well.
I hope this helps. If you have any other questions, please feel free to come back and ask.