A safehouse with food, water, and supplies stocked means he could wait in hiding for many months. If that safehouse is located in a very rural, he could do the Eric Rudolph thing and not be caught for years.
If the goal is escape to a foriegn country, all he has to do is make the search radius as large as possible and all that requires is he stays out of sight for a few weeks, then attemps to travel and has a very large and full gas tank because the more he stops, the more likely he is spotted.
Also, I'm not convinced he hopped on the interstate because I have been of the opinion that there are cameras and plate readers on every Interstate with facial recognition tech. If he was on I95, he'd have been caught by now.
My guess is he would have taken route nine to backroads that go into western Maine.