If you have to do hard surface roads which would be concrete (asphalt won't work) and footings, the cost gets a lot higher.Also check to see if you have to put in a Storm retention pond. 

And they might charge you a fee for cutting the pavement and degrading the road, and then you’ll have to pay a contractor to do all this work.

Even if your land price is double, your return will be higher since the building/fence/security/electrical/etc will be the same.The really big swings in building a Storage location are: Footings required, Concrete/Asphalt roads or rock, Sewer/water required for bathroom, fire hydrant required, storm retention pond or drainage, etc. 

You'll need to consider setbacks, covered vs uncovered ground (how much asphalt / concrete / building can exist), zoning (does the area allow multi-family or do you need a variance) population density requirements, building height requirements, and any other fun things that the town regulates. 

Assuming your CPA says it makes sense to do the cost segregation, the big ticket items will be asphalt, sidewalks, flooring, landscaping, site work for drainage and compaction of the area under driveways, appliances, wall coverings like drapes, fences, etc. 

The property needs a little rehab on the parking areas (broken up asphalt over years of use)Also some concrete steps around the entrance and patios need some new masonry work to keep it from further deterioration.  

The only time I leave it is if I'm having a metal roof put over asphalt shingles.

I tried getting clients in a similar method when I was pounding the pavement looking to jumpstart my Realtor career, and I failed.

Many of the ‘land improvements’ (pavement, concrete pads, fencing, landscaping, etc.) depreciate on a 15 year schedule.

So, starting tomorrow, I’m feet to pavement and will do more myself!