if it's important for them to be IN the room on arrival, you could always check in- get your room keys- have DH help you get the luggage to the door of your room- then send him and the kids down to the foodcourt to get your refillable mugs- if you buy them, or to check out the pool, or find the arcade for reference
Then when they get back- or better yet- GO GET THEM...and exclaim "you wont believe what I found in the room when I opened the door"....they wont know it was you, especially if you just drop the bags inside the door- and meet them quickly.
every morning, when we got to the elevator, I would "forget" something in the room- DH and the DD's would go down to the bus stop, and I would put out their tinkerbell gifts for the day I had downloaded the WDW font, and made them notes from characters I knew they'd see that day. Only 1 day did I have to run back to the room before them, and take the note, as I had cancelled a PS during the day...(it was specific to the lunch)...but this time, what I did was have DH take the girls to the arcade
good luck
Brandy