Honestly if I got one like that I'd set it up in a small QT tub so it's a little more humid than normal since most neglected snakes are also dehydrated. Leave it alone for 24 hours to settle, and put a warmed, damp f/t rat fuzzy in with it the following evening.
The only rescue snake I took in that didn't eat for me within 24 hours was the burned adult ball python that ended up passing away due to sepsis.