At 14 days out, she's really out of the acute phase of the sprain. Even with a bad sprain, it would be okay to have her bear weight on that ankle as much as she tolerates. If she can't tolerate bearing weight at all, then walking around WDW is probably not going to happen. If she can bear full weight on that ankle without pain, then walking around WDW is going to be fine. But you the tendons and ligaments of the ankle are still weak and stretched out even if she can tolerate walking on it. So I would suggest getting an ankle brace at your local drugstore or Wal-Mart to offer some support to the ankle. They make the soft ankle braces that you can slip on under your socks. They offer compression for the swelling and some stabilization.
Be sure to take rest breaks and definitely ice it for 20 minutes on/20 minutes off at the end of the day. Be sure not to put the ice bag directly on her skin - use a towel or something between the ice and the skin. If your wife is unable to bear any weight on her ankle at this point (14 days after injury), please visit the doctor as there may be some torn ligaments or tendons, or even a break in the ankle bones. If she can bear weight through the ankle though, she should be fine walking with the ankle brace and a few extra rest breaks... and the adrenaline that kicks in with a Disney trip is going to help, too
Hope that helps some. I'm a physical therapist, so let me know if you have other questions