Okay, I'm really sorry. I've only been online for about five minutes at a time this past week with the exception of times I've been online for work (and most of those have been short as well). Between working and site-seeing (and having to pay for internet access) it's been hard to find any time to get on the boards.
Framework4 and Elisabeth-
So, since I'm not really big on surprises, I will say that my take on this story (and where I hope it's going) is not the same as where I think the two of you are anticipating it going. I should explain, I think, that I'm not so much a Superman fan. I like him well enough, but don't make special efforts to see the Superman movies or anything like that.
I'm a "Lois and Clark" fan because I really like the focus on the characters. It's sort of an interesting case study on human behavior to see this man trying to balance two lives and the Lois in this series is more interesting (in my opinion) than many others in that she's just as complex a character as Clark.
Given that this is what I like about the show, it shouldn't be too surprising that the characters in this story are very real (I hope). So, yes, Superman is real (and as such is feeding Lois' Superman fantasy) and yes, Lois would easily spot the difference if Clark were to put on the Superman suit and come visit her. But that's not because the older Clark is trying to usurp the younger one.
He wants to go home to his wife and leave this Clark and Lois to their lives. But he's human (or enough so that he makes mistakes) and it's hard to be a robot. And even harder to not respond to someone who is so similar to the most important person in your life and someone you don't get a chance to see. So, he's screwing up. Not because he's evil or malicious, but because he's Clark.
As for how the rest of the world will react when Clark takes over for Superman, we'll just have to see, but I don't think it will be quite so obvious to anyone who doesn't know them both as men (ie, the Kents and Lois). It will take awhile for us to get there (yes, this is going to be a long tale), but Clark won't be such a beginner when he takes over.
I think the idea of taking this in a "Superman is evil" direction is interesting and I may even explore it in some other fic, but that's not what I'm writing now. This is our Clark, and he's inherently good (or at least that's my take on his character). He's just also inherently stupid when it comes to Lois.
I hope to post the next chapter before I leave Japan, but I haven't had a chance to go over it again yet. I'm home next week, though, so should shortly be back to a normal schedule.