Honestly I didn't think the floor looks as bad as you all are saying. I was thinking you can get by with one of those polish and rust treat kind of deals.
As noted, there will be a lot of parts expense even if you get to skip paint by use of elbow grease and polishing. You've got signal lenses and wiring issues at a minimum. I'd definitely bank on an engine refresh, so bearings and seals and then whatever you find in there. Tires, tubes. Brakes front and rear, maybe a cable set. Tank could be gummed up, probably needs a tap.
But if you do your own work, you can't go wrong with that bike at that price. The motor alone is worth more than that price, so at worst you could part it but I just don't think it would need to come to that. I would be prepared to be spending the $2k, and know that whatever you prepare to spend, you will need another $500 once that money is gone
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As noted - you can get a better starting point bike and end up doing less work and at the same total - but where's the fun in that?