First, let me thank Dave, Thomas and TIG for their willingness to investigate and provide insight. And while they they could not provide the Magic Bullet solution I was hoping for, the information they provided turned out to be very helpful. Eventually I was successful at draping the overlay of the parking layout onto the cad created ground model.
I will briefly explain the "fix" for those who might find themselves in the same situation.
The cad ground model was created by placement of shot points relative to a properly scaled jpg. satellite view of the property that included superimposed grid lines at 5' increments. The parking overlay was created in sketchup, exported to my cad program, and superimposed over the ground model. My thought was to assign shot points at locations where the jpg grid lines crossed over lines in the parking overlay so as to minimize the number of faces when exported back to sketchup. Big mistake.
Location errors that occurred from importing and exporting between the programs is what made for all those short short lines segments. When I went back and moved all of the shot points into free space, (that is not on or near a parking overlay line), the problem was solved. Drape worked without problem with this slightly modified ground model.
Thanks again, would not have figured it out without your assistance. Karl.