Woo. So stoked to see you work on the bikes again! Looks like the rust got in there pretty bad, but hey at that price it's a fun project! I'm going through issues with my honda 250 right now, and like you're saying, prices are crackhead.
I just bought a 83 250 that looks the same it has a rebuilt engine that came from the machine shop put in the bike and left outside for a year and seized up so im tearing it down it still has the plugs from the machine shop people are idiots once you fix it up you should be able to get a good wad of cash for it just don't let it go until you get what you want for it someone who wanted one when they were a kid and couldn't afford it and can now will pay whatever to satiate the need
The things I do for happiness and content, well I'll be making video of another financial mistake that's not a POS, or at least for for now. Might not be a financial mistake for what I do with it so stay tuned!