u could cut it with a small recipricating saw.... get it as close to seems as possible then sand it smooth..... u could could pry hit it with a hammer and break center out and pull the rest of pieces out pretty easy as well, it should be fairly flimsy wood in there,,,
i would make plexiglass doors where the wooden ones are so u can see inside it easier....
if u did like a slighlty riased floor in it u could pry do a heat pad in side it as long as between heat pad and wood floor was enough breathing area
i think ive seen some similar enclosures in the diy section look through and see, u can get some more ideas that way