Hi Lori,
First trip! Prepare to have the time of your life! I would love to help you plan your itinerary in detail, but I may end up writing you a book and the space for me to respond is very limited. It seems that you will have 5 full days and 2 travel days. For your full days, I suggest allotting one full day for Epcot, one for Animal Kingdom, and one for Hollywood Studios. Being that you are traveling with little ones, I would suggest you save two days for Magic Kingdom, as this is the most popular park. Between the character meet and greets, the parades, the attractions and the delicious dining options, the time will fly by! For your travel days, consider visiting Downtown Disney or if you are staying on property, you can explore your resort!
As for the “must see attractions” be sure to check out "It’s a Small World” and “Peter Pan’s Flight at Magic Kingdom; “The Seas with Nemo and Friends” at Epcot; and “Disney Junior – Live on Stage!” at Hollywood Studios. Let's not forget the princesses, so be sure to check out the Character Experiences!
I hope this helps as you put your plans together for your vacation. If you have a specific question once you start detailing your itinerary, feel free to ask me more questions!
Yael