You've been less than encouraging"

It's an almost value-less old bicycle, not the ceiling of the Sistine Chapel. If you do start ripping into it you'll be inundated with advice. Viz:

Start with bottom bracket disassembly. If the cups are corroded in and you mangle the frame getting them out, you won't have wasted too much time and effort on the rest of it. You'll need those spare cotter pins before you start.