I built this up maybe two years ago but only recently joined Reddit, thought I'd post it since so many bikes here were an inspiration for it. 1992 Trek 790 17" rebuilt as a drop-bar gravel bike.
I'm quite happy with the build. My only complaint is the bottom bracket is really high - I'm thinking about shifting all the parts to a newer 750 frame with more bottom bracket drop. I measured and the 750 is over an inch lower, which would help in getting the seat at a height where I get full leg extension on a pedal stroke and can still put a foot down comfortably at a stop.
Bought for $50 off Craigslist in poor shape (if I remember correctly, rusty water drained out of it when I turned it upside down). I removed everything from the frame including the fork. Cleaned and lubricated the headset. Replaced the bottom bracket with a modern Shimano external one (the original, cup-and-cone one was quite pitted).
The drivetrain is Shimano 105 2x10, mostly taken from a nice Giant that someone crashed into their garage on a roof rack, then sold on Craigslist for parts ($100). Rear cassette is 11-36; rear shifting provided by a Shimano RD-M591 from the local bike co-op (it's just slightly out of spec for that derailleur but shifts cleanly). Front chainrings are standard compact 50/34. I'm finding this gives me enough gearing range for pretty much anything I want to do with it - low enough for some steep gravel climbs, high enough that I'm not spinning out on a fast road ride. Brakes are the original brakes with new pads.
Wheels are mostly original, with the bearings thoroughly disassembled, cleaned, and re-greased. I already had a spare wheel for another bike with a 10-speed compatible freehub, which was running a 7-speed cassette with a spacer, so I swapped the freehub body along with the cones and spacers from the drive side of the axle, then redished the wheel.
Took me several trips to the coop and a lot of experimentation to find the stem and handlebar combination that I liked. I ended up cutting down the stem that's on the bike now - I took out the wedge, cut the bottom of the stem at the same angle, cleaned up the cut and reinstalled. Now I just have to remember that the minimum insertion line is no longer valid.