Many interesting thoughts from all who have posted here.
IMO, wherever these two are, they are just one step away from being spotted by a concerned citizen or LE officer that will bring this lamentable odyssey to a conclusion. They don't have much money, they are overexposed in the media, and they are probably exhausted and hungry. It's only a matter of time before Tad is arrested and Elizabeth is released.
Sadly, there are prior examples that suggest this could take awhile. Elizabeth Smart wasn't found for nine months--and was within 20 miles of her home when she was found.
I think Tad and Elizabeth are in the US, barely scraping by, and are just shy of being exposed, every minute in every hour of every day.