Hi Melissa....let's start your planning process and I think you will actually enjoy it once it is under way and you aren't feeling so intimidated.
You have picked the dates which is the week after Easter. Easter weekend will be crowded and the week following might be as well but it varies from year to year. It is important you plan ahead and make dining reservations now.
There are great things to see and do in all four parks for the age of your children. I would concentrate on visiting the Magic Kingdom at least two days and the other parks at least one day. That also leaves you days to enjoy the resort pools and other recreation or return to parks that were favorites for the family.
To make your trip especially easy you can book a room with a dining package. You can see these and compare what works best for you by clicking
HERE. This is a great way to pay up front a vacation and have no worries except for incidentals once you arrive. You have two basic options for tickets and if you think you will only want to visit one park a day buy the basic ticket. If you think you will want to visit one park in the morning and then one in the evening then be sure to add the Park Hopper option. I highly recommend doing this as you can visit a less crowded park for half the day and then head to another park where they will have Extra Magic Hours for the evening.
It is so hard to tell you everything in this short space. I suggest you buy an inexpensive guide to Walt Disney World and read through it to get a better idea of options and choices you need to make as soon as possible. Early reservations for dining are a must and they can be done now. A guide book will help describe the restaurants and menus for each. You can make those reservations on line or by phone 407-939-3463. Keep asking questions as we will help with each.