Our kids are similar in ages so I know how excited they (& you) must be to go to Disney! You're leaving in just a few days so I'll try to help as best I can!
I'm not sure if this is your first trip to Disney World OR just at a resort, either way you are in for a treat! If you are a 1st timer at a resort, one fun thing you can do is set up an arrival gift with
Disney Florist. I've had one that included a giant stuffed Mickey, autograph album, Mickey shaped snacks, light up Tinkerbell & even sticky Mickey footprints on the floor to look like the Mouse himself had been in my room. Talk about Magic! If you don't want to go that far, there are smaller packages that include Mickey ears, a disposable camera & snacks. This would be fun for your kids to receive when they arrive!
Another fun thing to do at resorts is to check out all their extras--sometimes there are special Hidden Mickey tours or special events for kids (like cookie decorating, scavenger hunts, etc.). Walk around & see all the fun the resort has to offer--it is a vacation in itself!
If this is your 1st visit to the parks, well, I hate to say it but just be prepared---look through the website & find the attractions at each park that your kids will like. See if you can book a Character Meal, make sure you plan to see a fireworks show and hit up all four parks. That's not to say that your vacation would be a bust without it--oh no! If you showed up on Disney's doorstep not knowing a thing about it, you'd have the time of your life. The most exciting & magical times at Disney are when you just walk slowly through the parks and experience it.
My greatest tip is to make sure you have a rough plan of what you want to do...but don't stress trying to do it all. Just enjoy the bits of magic you'll encounter along the way. If you have any specific questions, please ask me & I'll try to get to it before you leave!