There are new hollow spindle 2-piece cranks (sort of like Hollowtech II), crank with rings, and external bottom bracket bearings, for the price of just a couple chainrings, $65 with steel rings and I think $5-8 more for aluminum rings. This has been a great upgrade from square taper spindle BBs, especially for road; Some MTBers prefer internal cartridge BB, as the seals are further away from the crank arms, so no grinding of dirt between the two, as with external bearings they are right up against the crank arms. My favorite has been out on amazon for a long time, still on ebay, it's 50/34 on 5x110mm BCD. If you need lower than 34, you'll need a 110/74 BCD triple and I have not seen them aftermarket with hollow spindle at the deal I got, but they may be out there; I wanted a 5-arm spider just for aesthetics, 4-arm spiders are much more common now. 170mm is typical, not all are available with longer arms.
Also, the quality of cheap derailleurs has improved a ton in 25 years, you can probably get a decent one for $25. With your wheel size, you have tons of room for a long cage. I use a mid-length GS cage because I'm on 20" wheels and a long cage would drag on the ground. You can get by with a GS, I think you'd only need a long cage for a full triple range, and/or a megarange cassette for lower lows.
I'm old, and sometimes run out of gas climbing hills while standing, so need a 21 gear inch low to crank my way up sitting. To also have sufficient high of 85 gear inches, I need 400% gear range. You might want a higher high typical of road race bikes.