I think people overestimate the difficulty of living off the grid or evading. People here in Hawaii do it all the time, and yes, many evade police for years, work under-the-table jobs, and so forth. Admittedly we don't see the kind of manhunt Washington is doing.Seems to me if he intended to take his life, he would have done so soon after the killings, meaning he would have been found. Either he's really, really good at being off-grid, or he's elsewhere.
This guy was trained in evasion and survival against an enemy with high tech gear looking for him. He would know the techniques searchers use and how to evade them.
Some Japanese soldiers evaded capture for years, almost 3 decades in one example, after WWII. It can be done.
I think he slipped out of the perimeter early on and is now someplace with a mild climate where people don't ask a lot of questions, possibly with a new identity and a completely different appearance.