Hi Mike,
Without a more detailed description, and a lot more photos, this is going to be tough to evaluate... but I've got a few initial thoughts:
1. This might not even be a Scrambler. It could be a CJ7 stretch gone bad (check the VIN).
2. Half of the body is homemade, and half of the frame is homemade, so it is not restorable by any definition. Any "Scrambler" collector value is out the window.
3. The running gear is really what you're buying... is there anything special about it? A 5.3 with an Atlas transfer case and Dana 60s might be worth the asking price, but a stock drivetrain, not so much.
4. If you want to buy this Jeep, I hope you're VERY confident in the frame extension, especially where the new tubing attaches to the old frame. Also, if it runs and drives to your satisfaction, I think $2500 would be a better target price.
What are you looking for in a Jeep?
If you really want a Scrambler, I'd say hold out and spend a little more money on a better example.
If you want a Jeep that you and your family can go out and enjoy today, I think $5800 could buy you a decent CJ7 or YJ that is ready to wheel.
Good luck!