First, shot at Michael's Store, Michael's is in a strip mall and the only windows face toward Aspen Hill Road (Below the star in your map)
Second, the Saddle Brook Park in the second map is located behind the shopping center complex. The victim was out front in a large parking area.
Third, I don't know the layout.
Fourth, too many buildings to block site of 95% of your circles. The way the gas pump islands are situated (perpendicular to Rt.185) and the victim was in the process of pumping gas, he was hit in the chest ruling out a side shot because the pumps are too high and the other direction is obstructed from long range view, the shot would have come from the Giant Food grocery store parking lot directly across from Rt.185 (Connecticut Avenue) in the extreme lower portion of the circle.
Fifth, the victim was sitting on a bench in front of a store that faces out into a parking lot. The parking lot's grade rises as it gets to Georgia Avenue where it levels off. The green across the roadway is a residential neighborhood.
Sixth, the shot is believed to have come from across the street in the Safeway grocery store parking lot. That is one of the locations that a "white truck" was seen leaving the area.
As for the others the timetable suggests that getting around on foot is a possibility and I can't tell you what the lay of the land is but the Wednesday-Thursday shootings would have to have been mobile. Time would not allow for any walking and the only logical shooter locations are in the surrounding parking lots.