There is a few maps here you can download.
 
All maps in one zip-file
 
Here is a few cheatcodes (type them in wile your playing)

dnstuff = All weapons and ammo
dnkroz = you are immortal
dncashman = duke spews money when you hit the spacebar
dnscotty%$$ = when % is the number of the episode you want to goto and the $$ is the number of the level
for example: dnscotty308 then you come to level eight on episode three (hotel hell)