Self storage costs of a closed business

Not even sure where to start.  I found a closed self storage unit around 30 units.  If this was a functioning property and full or close to full 90% or higher what would be a good price? 

It’s going to take me months or even a year to fill the units.  Need to get marketing going and a lot of deferred maintenance.  

My research for what I can get it to based on area comps and maximizing the space it would make a great return. 

So questions what’s a 30 unit worth, and any tips to get the seller out of crazy land and back to reality.  what % could I get this for?  It’s around 6,000 rentalable square feet and at .80-.85 per square foot of rentalable space.  

Thanks.  I’m sure I sound like I’m rambling but I want to go in strong but realistic to the seller.  

    Some thoughts I’ve had is seller financing to get the sellers bottom line moved up, a profit share for getting the units refilled, or maybe even a kicker in a few years of stability.  Just thinking of road blocks that people have been throwing down that I can overcome.