If you look at it as the reality of science and the reality of supernatural meeting, then you've got some pretty good interaction and clashes. Can you imagine Lois' reaction to Marcus' story? Remember her reaction to the Invisible Man of the first season of L&C? - total disbelief until she was given proof. Remember Perry being skeptical of a flying man until Superman flew into the bullpen with Lois in his arms? Now as Clark has traveled the world I could see him perhaps being less skeptical, as he might have run into unexplained phenomena that could potentially be explained by the supernatural (i.e. death by exsanguination, with two holes in the neck).
Who, besides Lois and Clark (and Tempus, Andrus, and H.G. Wells) will believe in time travel or alternate reality travel? If they talked about it to other people (well, except for Martha and Jonathan perhaps) they would be labeled insane.
You can look at dimensions and realities from a scientific standpoint, albeit theoretically. Time travel too in fact:
Alternate realities, as we've seen in Lois and Clark, are side bye side, running concurrently, with each realities growing progressively different the farther they are apart. A reality exists for any potential action, whether the reality has always existed or only came into existence when a particular action took place is unknown. With the Alt World we saw in L&C, Lois was supposedly lost in the Congo before ever meeting Clark. That's a pretty big difference from the reality of L&C. But, as things besides Lois' absense were present (James Olson owning The Daily Planet, Perry White running for mayor) the Alt World had already been set on different path. Something as minor as a person deciding to have a tuna sandwitch instead of a BLT could create a minor change to an alternate reality, one that might not even be noticed unless it was combed over with a fine-tooth comb.
Dimensions are successive layers of the same reality. They sit one on top of the other. Think of it as a cup full of liquids of differnt densities (i.e. oil floats on water). There are ways to get around the layers and "punch" the way through to a different layer. If you were to put a drop of soap in the oil layer it would push to the edges of the glass, thereby revealing the layer beneath it. The same is with dimensions. Dawn Summers, being the human form of the Key, can be used to skirt around or even just punch a hole in the dimensions.
What I forgot to post last night was that the Knights wished to kill Dawn before Glory could use her in a blood-letting ritual would not only allow Glory to get home to her dimension, but it would indiscriminantly rip open all dimensional barriers and quite literally bring Hell on Earth.
I'm rambling, but what I'm trying to say is that in essence, worlds are colliding. Lois is and will be learning about a world entirely unknown to her.
Oh! As for the dreams she's been having, the blood on her hands, etc... they could very well be Slayer Dreams. What are Slayer Dreams you ask? Well, each Slayer has prophetic dreams to a certain extent, including dreams of past slayers. Some have stronger precognitive dreams than others, depending on their natural inclination towards such things. The blood on Lois' hands could very well be from her time in the Congo and what she had to do to save herself, but it could very well be a dream of something to come or of something already passed.
