Hi Mike!
Disney Vacation countdowns are the best! You're almost in the home stretch!
I have kids about the same age as yours, and I prefer to keep their KTTW cards without charging privileges just to avoid the hassle of one being lost etc.
I think the best (not to mention FUN) options are a Disney Gift Card (choose their favourite Disney Character and/or colour scheme) or ... Disney Dollars! Denominations available include $1, $5 & $10 and each has it's own Disney Character Portrait. They're a great tradition in so many Disney-loving families.
Disney Dollars may be purchased a couple of different ways. The first and most common method of purchase is at the Walt Disney Resort in Florida. They're available at Guest Relations at all four theme parks and the water parks as well as at all Disney Resort Hotel front desks and concierge desks.
If you'd prefer to receive your Disney Dollars in advance of arriving at Walt Disney World - well ... you can do that too! You may choose to purchase using a credit card by telephone and have your
Disney Dollars delivered to you for a $15 shipping charge. To pay by credit card, call (407) 566-4985 and select Option 5. You can purchase $50 per day by this method of ordering. Advise the Cast Member of the denominations you'd like to receive.
You can also choose to order a larger total amount by mail. Full details for payment methods & mailing address are included in the link provided just above.
Wishing you a simply Magical time on your fast-approaching Walt Disney World vacation Mike!
Kirsten