As the title suggests--I hope you'll bear with me, because I'm coming in from out in left field with some thoughts on this case. All my opinion, all just speculation based on reading through all the threads and some googling and some out-of-the-box thinking.
1. Lyle (for lack of better name) was extremely thoughtful, private, and meticulous in his suicide. Thoughtful seems an odd word, but I think he tried to do it in a way so as not to hurt people close to him. I think it even bothered him that the maid he met two or three times might open the door to such ugliness and made the sign "Suicide" to put on the door to warn her then decided instead to hang himself the other way (back to door) so the public note wouldn't be on the door, insuring his absolute privacy, like the window cover and pillows and moving rooms. This was a ritual to him--probably played over thousands of times prior to actually doing.
2. For a meticulous, detail oriented person with a well-thought out plan, some pieces don't make sense, most especially for me--- Why misspell Stevi(c)k? I don't think he would have. I think he had every detail planned, including the check-in name. I think he was educated, as everyone else does, and it was a private joke or inside meaning maybe only with himself. I absolutely think he had the name in mind and did the misspelling on purpose. Now here is where I go to left field.....Lyle Stevik is an anagram for either Y Kill Steve or Kill Stevey. Which I figured out prior to getting to the part of the first thread about the A.S.H posting by "Steven" a few days prior. More on that in a minute. Anytime I see a fake name, I just doodle around immediately for an anagram...so he knows the name from some book he had to read in college, maybe, and had figured out at some point what a clever clue it was?
3. Why the Idaho address? My guess is that is where he stayed the night before. As the threads prove out--he has a multi-ethnic, normal guy, blend right in, face. Motel/hotel staff see "him" a hundred times a week. So three weeks later when the local LE go to the Idaho motel? Assuming he didn't stand out, and I bet you he would have made sure not to, nobody would remember him. He was probably sure he was entirely forgettable--who else would kill themselves if they didn't think that?
4. Why is nobody searching for him? Family? Friends? Colleagues? Because they know he is dead or they think he moved on. Think about the timing.
Between 20-30 years of age--he could be a college or grad student. Says goodbye for the year to his friends and colleagues in May and just doesn't show back up in September when school starts. People may inquire, email, call but in the end, assume, he just dropped out and went on to something else. Didn't you have friends that just didn't come back to college and you lost touch with pretty quickly if they didn't respond? And at that point, it is easy to drop 30-40 lbs over a summer without anyone inquiring about it.
And going back to how thoughtful he was (I know, weird word for the most selfish thing a person can do, IMHO) I cannot imagine he didn't write goodbye notes at some point to whoever his loved ones were. I know most people don't, but no aspect of this puts him in the "most people" category. I, heartbreakingly, don't think he will ever be identified off of missing persons because I doubt he was ever reported missing. His family knows he committed suicide and if he told them they wouldn't find him, perhaps they didn't want to prolong their agony and just accepted....this was not an impetuous act, so my guess is his loved ones knew the truth in the note....and maybe want to NOT find a body to believe he didn't do it?
5. Could he be "Steven"? I absolutely think so and feel pretty sure he was. Steven's primer described a bit of a different ending for him, but when I read that, it felt false. He wouldn't share, even in death, something that private--his exact method--with the world, it felt fake when reading it the first time---my goodness, what guy would borrow another guy's *advertiser censored* ring to commit suicide?? That makes no sense from everything else "Steven" said in his text--assured, self-deprecating, aware, amused, sardonic, committed, educated. A belt would have been much more in line, I think. A belt that maybe was part of the whole ritual--"once I get to X notch, I will do it", something like that. Much more like the voice of the man who wrote that email.
Also, yes, the dates are off but I think taking out bad assumptions, or allowing other assumptions, they work perfectly. The webmaster at ASH noted that he/she assumed note was sent on a time delay and, as such, the author was successful. Bad assumption, again IMHO, when it was finalized and sent 30 minutes prior to the first plane hitting the WTC. So he puts it on a delay send---what maybe 30 minutes? an hour? much more and he has too much time to chicken out and the sending of the note makes him work on a "deadline"--it gets sent and he can't pull it back and feels he "has" to go through with it.
It gets sent-- why? Ok, maybe because he was successful, but, just as likely, because the phone lines all went bezerk at 8:15, less than a half-hour after "last updated" by him--not just on the east coast but particularly on the east coast. All circuits were busy everywhere!
Also possible? Method didn't work, he lost consciousness, lived, someone found him, rope broke, who knows...but probably email set to be sent prior to him recovering and getting back to his computer.
Another possibility? Steven, also being extremely detailed, meticulous and "thoughtful" like Lyle, notes in his missive that it will be horrible for the loved ones who find him. Let's presume he then intended to do it away from his loved ones to save them the trauma. Maybe he lives away from them (student theory) Maybe he finalized the note and heads off to the airport to fly somewhere to do it--with the ritual/sacred rite feel of his text, I could see him making a vacation of it. Well, that didn't work. The planes stopped flying pretty quickly that morning and the entire US airspace was closed until the end of that week, IIRC. So, he is foiled with flying, but, the note is already sent. No amount of meticulous preparation could foresee 9/11 happening the same day you decide to off yourself! People were going about their daily business---I was in the middle of sending a fax when someone said a plane hit the WTC, maybe he was in the middle of carrying out his long-planned suicide if that was his daily business, you know?
6. Gray's Harbor, WA then? The timeline works, though, from about 1/2 to 2/3 of the US, unfortunately. Working backwards, and I am discounting Canada for many reasons but this is already too long so maybe another time, he arrived there on 9/14, using the address of hotel about a day's Greyhound away from there in Idaho. Backtracking from there, adding in Greyhound's routes and time tables (obtained from website), Gray's Harbor from Portland, from Boise (Meridian) from Salt Lake City from (a) most of the SW US, (b) Denver thus most of the midwestern US. Easy trip from Chicago, St. L, Kansas City, not even riding bus overnight. If riding bus overnight, can be from anywhere pretty much.
As CCM said, his town is pretty much the end of the earth. I live in NH and could tell you exactly where people think the eastern end of the earth is--in Maine.
All in all, very depressing because I think he was never reported missing, is missed but known to be dead by loved ones, could have come to Gray's Harbor by Greyhound from pretty much anywhere in the continental US--many of the northern states having accents like Canadians (I would think a WA resident could easily assume a Chicagoan is Canadian with only a 30 second check-in conversation--the o's and a's), made sure no friends or colleagues would be looking for him, left a few clues because he was too smart not to want to brag about his "feat" in some manner (ie name and ASH missive) and as such there is a very low likelihood he will ever be identified unless a friend/loved one/colleague/whomever happens across this forum or others about him. Extremely sad but I cannot see any other answers based on the information available.
I would love to be wrong and I know I'm coming from left field, but I just don't see how to narrow down from those possibilities, which makes the task of ID like a needle in a haystack.