While my previous post stating 45 minutes is accurate via WDW transportation, I would follow the other suggestion of taking a cab. A small price to pay for the time savings.
When we travel to WDW, we do not rent a car. I am pretty happy and content to use WDW transportation to/from the parks. However, I find the WDW transportation between resorts to be hit or miss. Sometimes good, sometimes very slow.
Specific to the MK resorts, I would really like to see a walking path from the GF all the way to WL. It is only about 1.5-2.0 miles. It would be great for runners, walkers, etc. While I may not choose to walk all the way to GF from WL, It would be less than a mile to the TTC from the WL. I would be willing to walk 10-15 minutes to catch the monorail from the WL.