Let me first begin by letting out a big, fat resounding "HA!" I mean, I'm not one for the "I told you so"'s, not really anyway, not often, because well, let's face it, when do I ever really get to say that to you? But I mean, I told you to wear something. SOMETHING. Anything at all, even just a light summer cloak, but did you? No. You didn't! A sweater, I left you one of my sweaters and what have you done? You have caught a cold, which means you haven't been wearing said sweater. I'm sorry, however, that you're sick, and glad to know it's not going to impede any visit. And you should listen to James's mum. She knows these things.
I'm glad you're coming to terms about the head boy business. I don't...I still don't quite understand it, but at least one of us may. Or may at least be able to accept it. It's not that I fault James, or think him incapable, because really, I don't mate, but I mean, it just seems odd having been prefect the last two years myself. I'm not saying that I would be better, just that I wonder what Professor Dumbledore's up to.
You bloody well better not give up on the Marauders. You have finally got me liking the name, therefore you can't give up until you have me seeing the elephants! In an answer to your question regarding the stairs, I have one word for you: LATIN. I've been, well I've been researching that thought myself because that was one of my original quandries, but I think I've solved it. There are a few lesser-known protean charms that can...well it's hard to explain really but they can detect certain movements. They can figure out where certain things are if you use the right phrases; I mean, we're not going to be drawing the map out line by line like any boring Muggle map - the corridors the barriers, everything will be broken by charms and spells. It's going to be a bit tricky but I really, really think we can do it. And if Filch ever gets his grubby hands on this I WILL DIE*. Literally. I won't leave Hogwarts without it.
All I can say, really about your family is that I think you should go. I know you haven't talked to your mum in awhile but it might be good - I mean, what could it hurt? If you really feel like you don't want to go then don't, but you should. You just...yeah. I think you should. Let me know if you hear anything else.
*- and NOT of boredom.