I hate to say it but the basic adventure games with those features that I know of are mostly just thrown together ad hoc, it's pretty basic programming following YAGNI principles. There are no diagrams, UML, or extensive documents except for the scripting language chosen and the interfaces the designers can use. I've never seen any, at any rate.
That being said, one great example to check out would be SCUMM and another, more elaborate example would be LPMUD engine code which has all those features and could be downgraded into a single player experience with some work.
This forum itself is a good resource but you must narrow your search to just one feature at a time to get the best results; even then you're going to see a lot about techniques and very little in the way of diagrams.