I got this from a Goodwill auction a couple of years ago for my wife. She liked the color and it came with Sora 8 speed brifters. Good stuff for a lady that doesn't ride that often. I have upgraded a few things but what I am trying to find out is what is it?

It's welded, has diamond shaped water bottle braze ons. It sounds like good steel when you thump it. If it was my size I would ride it myself. It has a serial number which is> H1L02042. The dropouts have nothing there. It looks like it never had decals and if it's a repaint it is a pro job, IMO.
Any thoughts? I have googled a plenty. I can take more photos, these are what I have right now. Perhaps it was a custom job for someone.

Strange that it's TiG welded but with that classic chainstay bridge and reinforcements around the WB bosses (which would be brazed). Seems like a hodge-podge such as for a "custom" or even a frame building class project.
Have you removed the fork and if so is there anything on the steerer?
What size seat post?

I have not removed the fork. No need for headset rehab yet. Seat post is 27.2.

The fork (steerer) might have a clue either stamped on the outside or if there's "rifling" inside...but at least the 27.2 seat post is a good sign for quality tubing. Other than that I have nothing!

It can't be a hodge podge frame building project, it has a serial number. A far fetch guess is a Fillet Brazed Schwinn, but I'm sure I'm wrong.

anybody with a stamp set can make a serial number, I have one: what would you like? I'm trying to guess if this one could be some kind of a message: "Hilo-- to you, 42" or something like that.
But, it could be a regular production frame from a big builder that mixes brazing with TiG welding of the main joints. I just can't think of who that would describe.

Might be fillet-brazed rather than TIG'ed. Braze-ons make it look Japanese, mid to upper level.

What's the threading on the BB and fork?

I reckon it might be...tho the OP said "it's welded".
I'd like to see a shot of that seat cluster, can't make out it there's some kind of lug or plugs for the stays.

I like it. Fastback seat stays and 27.2 seatpost scream quality. Oh, and that chainstay bridge treatment is another good sign.

I will take some photos of the seat cluster. And a few other areas. I am guessing it's about 23 pounds but have not weighed it yet.

I put a Shimano Octalink BB in it, English thread. Don't know about the fork threading.

I was wrong. It's a 26.8mm seat post. Ooops.

Not so sure: it looks like the slot's pinched as a result of a too-small seat post.
What do the experts say: is this fillet brazing (of the main joints) or TiG welding?
Nice paint...I'm still not convinced it's anything "production".

I had not considered that. I will expand the slot and see if it will take a 27.2 SP. It's not going to bother me if I have no idea what it is. My wife won't care for sure. She is satisfied that it has some Dura Ace bits on it.

it doesn't look like a production bike to me.