@ Les, yes I know what you mean. In wish they had designed the kit to be easier to build all closed up, but I have to work with what you have. Building this kit has made me even more appreciative of your results with this kit! Feel free to chime in here if you have a better way to do something based on your build experience

On to the update!
I've made some progress on this beastie. Unfortunately, it's not pretty. With the kit being engineered to be all opened up, I expected to have some fit challenges of course. As mentioned above, other builds have indicated that getting the wings and tail attached to the fuselage is a challenge, so I did some dry fitting and found that I could get a good fit on the wings if I was able to put pressure on the join from the inside of the fuselage.
So, as mentioned above, I decided to be a bit unorthodox and build this kit by attaching the completed wings to each fuselage half, and then attach each tail section to each half, and finally join the two halves of the aircraft together.
But, before I could do that, I had to do a couple other things. I finished off the cockpit by adding the control rods to the control horns I made previously:

Although you could probably fit the rear quarter windows pretty easily when the build is finished, I decided to play it safe and attach them now. One note of caution, the plastic Meng uses is pretty brittle, so trim the part from the sprue leaving plenty of "stub" and then sand that down to remove it. Otherwise you could end up fracturing the clear part. I also noticed that the Gunze "type S" cement I use turns all the Meng plastic whitish where applied, and as such, the join between the clear part and the fuselage was a bit whitish as well. So, I masked by cutting some thin strips of Tamiya tape and outlining the clear part just inside of the join. I then filled that in with liquid mask:

Now that part is over, the fun part can begin. I started by attaching the wings to each fuselage half. As this required at least 5 hands and 80 fingers, I didn't manage to get a photo of it as things were moving pretty quickly as I had to manually apply pressure on the join to get it to fit. The good news is I am pretty happy with the fit, and the wing fillets don't stick out as much as they do on some other builds.
I then attached the tail (and tail fillet) to the wing/fuselage half and got two aircraft halves. Good for mounting on a plaque I guess

As you can see the fit is not prefect but it's pretty good considering:

I left the upper rear fuselage join between the fuselage and tail loose as I'll need to be able to pull it in to fit the spine cover once the fuselage is joined:

Since I was "on a roll" I stuffed everything inside the fuselage that needed to be there and glued them together. Starting to look like a "Komet" now!

I'm pretty happy so far as I've managed to get a pretty decent fit without filler so far, and after I get things wrapped up I am certain I can correct the few small issues with a little Mr. Surfacer. The good news is that my model will probably have a better panel fit than the real thing, in spite of the Meng's engineer's efforts to the contrary

Sorry I didn't photographs of all the stages, hopefully the ones above are enough to illustrate what I am describing.
Thanks for looking! Comments/critique/questions always welcome!
Doug