I do not think so.
Maybe he picks the area in will shoot in and then waits for a white van to appear and then does the deed.
Then he has to evade capture. Running or getting in a vehicle would surely make his capture more likely.
Are then any drainage systems/tunnels in the area that this man could be moving around in? Or just moving slowly in the woodlands, if the police think he will always try to be running, they will not really search a large area after a shooting.
In Yorkshire England in the late 70's or 80's there was a person who tried for the SAS and failed, so he went on a sniper-shooting spree.
They had to get a SAS tracker in to find him in the end and when they did catch him, they were actually inches away from him when the track saw him on the ground camouflaged.
He was shot. But it did take weeks and they were searching everywhere, but sometimes maybe it’s the obvious places to look (shooting area), rather than the roads and highways.
So get an experienced Tracker in and Track him down like a dog.
I also think the card was a decoy as the man knows they will bring in profilers. Which is leading the police in the wrong direction. Stay Safe
No to the tunnels; the location is not far from the Interstate, nor from any other well-traveled highways. Of course, it's on US 1, but if he went south, US 301 is not far away - 301 would be the first place south of DC where he could hop the Potomac (I'm thinking he might head up the opposite side of the river to stay away from the cordons, which are concentrated on 1 & 95).