I found a short article on another site listing what we know about Jones' exploits in WW1 and WW2 from various sources:
http://indianajones.wikia.com/wiki/World_War_II
This page suggests there is a series of fan fiction stories about Jones' WW2 missions, but I'm not seeing the stories themselves (maybe nobody wrote any yet):
http://indyfanfiction.wikia.com/wiki/Indiana_Jones:_The_World_War_II_Chronicles