fresco,
Our minds do create a spacetime context to concepts, and this is because the mind has a built in precondition of space and time. The "fitting in" you're describing is the attempt of the mind to describe a concept without having information of the concept. If the concept is a thing that can be shown, then when the person senses the thing, the person might have to change his or her view of it.
In terms of concepts influenced by social and linguistic conditioning, I believe that when the concepts are detached from these factors (well it's harder for linguistic) they can show a basic, common representation of reality. In the example of "water he crosses" and "water he drinks," both ideas refer to a common thing we call water ( the tribesmen too see that there is something in common). "-he crosses" and "-he drinks" are description of functions of water. The distinguishment between the two ideas are a result of the creation of complex ideas from these basic ideas.
If we were to talk about reality in terms of what we sense, then we see that there are sets of preconditions for this also. We sense colour for certain wavelengths for example. However, our senses are direct representations of reality because our senses are directly caused by interactions from direct external causes.
Because reality cannot be observed without there being an observer, we can observe reality using our senses, and it would be real to that extent. In order to maintain the "realness" of that observation all the time, we have to understand that our senses are limited and that they are representations of reality. An "objective reality", requires a representation of reality, imagination, and a rational faculty to connect things together.
In a nutshell, I do agree that we are working toward a common set of complex ideas that fits reality, but I think you're using the word "reality" too loosely, as I sometimes do too (I blame it on the English language

).