a lot more to this story
Perhaps there is but when a person has no personal debt and lives with relatives or in a homeless shelter, all income is disposable.
He was a strong healthy man with good mechanical aptitude, (I heard he bought the Caprice for $300). I can see how he might be able to scrounge enough money in odd jobs and odd crimes to bum his way around the country.
I will be surprised if he turns out to be some kind of sleeper.