If you fit your CO2 tank in the center, you could keep the door on (minus bottom tray thing). My only issue when I did that in mine was access and just plain fitting regulator in their right. A lot of people will actually turn their regulator horizontal, as opposed to vertical, so it will fit. I just didn't like doing that, and made it a real pain to adjust.
Like the drip tray Bsquared- I was going to get a tray with hole and do that with mine, but settled on the surface mount because of depth issues (even with cutting out the plastic the tray would be sticking out- not necessarily bad, but didn't know how clean I could make it, and didn't have any type of trim ring idea).