Good point. We must not forget that our perception of time essentially governs the structure of our lives. Take away time, and nobody knows what is going on. And, as we all know, you get time jumps in dreams quite frequently; rapidly switching from one location to another, landing in a completely different place at a totally different time. It may be that this happens and then we try to rationalise the experience upon awakening in our dream reports; if we dream about being in two vastly distant locations in a short period of time, we may confabulate and assume that we must have taken the time to travel there as well. It could be as simple as when we think of a location in a dream or experience something that is associated to it in some way, we suddenly end up there.
I'll have another look around the archives and see if I can find any more research on time perceptions in dreams.