If you are talking the actual drive-time I would say 10 minutes. If there is a potential for waiting for a bus I would suggest estimating a half-hour if you have plans.
If you want a different route one day and are not time-sensitive, then take the water taxi to Epcot (or walk), walk thru from the World Showcase gate to the front exit and take the monorail over. Time-consuming but it was oh so pleasant. It's nice in the morning when you are going along the one side of the World Showcase before it is actually open. Very peaceful.