It's worth what 1) someone is willing to offer and 2) what the seller is willing to accept.

Remember, even though it's low mileage, there's a good chance many seals and things like tires have deteriorated just due to age.  I suspect there will be alot of startup maintenance on ithis one.  Additionally, in some states you have to buy all 'missed' plates and pay a fine/fee to do that too so it can add up to a large amount of $$.  Figure it will take tires, seals in the engine, tranny and differential for a start.  Could also include things like relays and wiring too.

Unless you're a collector (which it doesn't sound like you are), an exceptional 86 probably would go for over $10K, but even that's relative.