Too bad there are no under hood or interior pics. Pricing is in the ball park, depending on true condition. Do a thorough inspection.
What does "not driven in 10 years" really mean. - Not started? Not registered?
Check with the DMV if there are any retroactive fees owed in order to get it registered. In CA the buyer inherits all the owed fees. Your state may be different.
Basic stuff - check condition of oil and coolant - the levels, color and smell. Water in oil? Oil in coolant?
Bring a battery with you. I'd pull the plugs, squirt some oil in and confirm that you can turn the engine by hand. Bring a big crescent wrench for the nut at the end of the crankshaft. If you can turn it by hand, connect the battery and see if it will at least turn over.
It looks like the fenders are from a '70 so check for front end damage underneath and on the inner fenders. Maybe they were swapped for cosmetics or rust.
Since the car has been sitting, expect that all the major hydraulic components will need to be rebuilt or replaced. If the brake fluid isn't clear it is a sign of moisture and deteriorated seals. The calipers and cylinders are likely rusted inside. If they don't leak now, they will in a few months once the seals wear over the internal corrosion.
If you can get the wheels off the ground spin them and see if the brakes will grab. Also inspect the front suspension for wear - ball joints are pricey.
Budget $1000 in parts, excluding suspension and soft top, to make it a safe runner.
Use that in your negotiations.
Some reading:
http://www.datsun.org/roadster/resource ... guide.html
http://www.311s.org/pmwiki-311/pmwiki.p ... uyersGuide
http://www.datsunroadster.com/misc_page ... _guide.htm
http://www.datsuns.com/roadster/roadsterguide.htm
Good luck. Let us know how you make out. Take some pics and post. I'm sure others will have some advice as well.