Before you get too far ahead of yourself, you should probably get an idea of what you want to build otherwise you’ll just be throwing parts at it.
You can go to bike co-ops, if they are around, and go a more vintage route or go with more modern components, which might get costly.
If you have any idea the type of gearing you want that can drive going to compact crank or triple or ???. It might be wise to ask at shops what is preferred in your area.
No matter how you go, I would spread the rear dropouts to 130mm and plan on running a cassette rather than a freewheel.
John