My primary interest in the level infobox was its "last level / next level" feature, which is handy because of the linear order of RE5's rooms. My other concern was that it might take a good bit of prose to describe where items/treasures are, especially with a large area like the Marshlands, so the "items" portion of the room infobox wouldn't be handy enough.
Overall, I was just shooting for consistency across the 48 "location" pages, but I wouldn't be heartbroken if you opted to change some to the room infobox.
Well, that's what the room infobox was designed for. I understand what you meant by the linear nature of the game, though having two rooms on a list wouldn't shouldn't people, especially given the naming. When it comes to the items field, you just have to say that something is set to be there - a key, for example. You leave it to the body of text to describe specific locations.