Map of MSP

I don't think there is a D42. But from the F concourse to D is not so bad, there's a central area full of shops and a slight ramp getting out of F. The D concourse is small, really just one big room.

MSP does have "flag-down" golf cart service to go from concourse to concourse, consider that.

You don't want to have to go from the extreme A's to the F's, or the extreme G's to the D's. For these, even able-bodied passengers sometimes make use of the golfcarts if they're on a tight connection.