This is a good start to get a bike back in circulation. You could sell it on and make at least 10x your investment. So good job for snapping it up.
I have brought back a couple of basket cases and I own a rider 400-4. My opinion is that this bike would be a $2,000 and a 6-12 month project to put back into rider condition with decent finishes.
I started working on bikes after my kids were out of the house and I find it relaxing when I don't have too many other time commitments. My bills are paid and I have a little play money. I don't know your situation, so think about whether this project will help or hurt your daily stress level. Having something like this "in process" and taking up space is a real commitment.
I guess I'd suggest that you think about what you want to accomplish.
If you want to have a bike to work on and ride, and you're not too concerned about looks, and your body fits this bike (you are 6'-0 or shorter) you could fix it on a budget and keep it. Probably $1,000 and 6 months if you have the skills and tools.
Parting it might sound like a way to maximize your return, but you have to tear it down, spend time selling and shipping parts, and what do you do with the leftovers? The folks who make money junking bikes do it all of the time. Do you have time for that?
Maybe you could make a grand in cash if you got it back on the road, but that's not counting the value of the time you'd put into it. Plus you have to buy parts and get painting and plating done. Your profit margin gets pretty slim, and you have to do top notch work or it's not worth much at all when you're done.
If you want to maximize the value of this bike in financial terms you should flip it right now. You bought it right, and I think you can easily make 3 to 5 hundred bucks without a lot of time and effort. If you get a title and make it run you'd be in a better negotiating position, but there's value there right now.
Just my opinions, but I congratulate you on a great deal. I suspect this won't be your last score in the world of classic motorcycles.
John Eberly