If you don't need to drive anything in or can drain the tanks after they're inside (I would drain them before arrival, so the fumes won't fill the place), maybe the storage owner will allow them. I stored my mower and snowblowers after running them dry with the valve closed, then drove to the location- by the time I arrived, the fumes weren't a problem.Likely to be in between places in due time, gotta find a safe storage place to keep my mowers & shop stuff.
This would be temporary till I can get a piece of land prepped & add a house & shop. (That's the plan anyhow),.