Not sure about Kissimmee, but I know the one Big V is talking about... that one is awesome it doesn't matter what time of day it is it is never "packed", we have been there in the middle of the day, over night even 2 days before Christmas and never felt that it was "very" busy. It is about 15 minutes (7 miles) from WDW property (depending on where you are staying of course).
To get to the one in Clermont (it is not really in Clermont so those that know where Clermont proper is it is not that far), you would go out to 192 and make a right (west 192...away from I-4) follow it until it ends at HWY 27 and make a right (heading towards Clermont) It will be on your right about a mile down the road.