It depends on the park, season and the day.
It's important to know that the parking lot trams that serve the regular lots do not serve the handicapped parking lots/areas. There are wheelchairs at the handicapped lots that can be used to get from the parking lot to the area in the park where wheelchairs/
ECVs are rented. But, the 'corrals' for the wheelchairs are in a central location, which may not be close to where you actually parked. And, there are often no wheelchairs in them because they have been used and not returned.
If your friend has a wheelchair or
ECV with them, the handicapped parking will be best. But, if your friend is planning to walk into the park, the shorter walk will usually be to use the regular parking lot and parking lot trams.
A valid handicapped parking permit is required to park in any of the spots with blue painted lines or handicapped parking signs. If your friend doesn't have a permit, they may still be directed to the handicapped parking area IF they have a wheelchair or ECV; just park in spaces with white paint. There is still time to get one from their state if the trip is not in the next couple of weeks.
The Studio has the smallest lot and our experience is that if you get there after 10:30, it might be already full.
Epcot has a large lot, but you could be parked at the far end of it and will have a long walk if you don't have a mobility device eith you.
We never park at MK, so I can't answer except to say that it is a long walk.
AK's lot is not that large and can fill quickly. In our last trip this Spring, there was a CM at the entrance to that lot checking for handicapped parking permits.