Examples could include:Partnering with other investors to share risk.Using seller financing or lease options.Leveraging creative rehab techniques to save on costs.Negotiating with contractors in a unique way to reduce expenses.I’d love to hear any stories, tips, or approaches that helped you pull off a deal others might have instantly passed on.

Zoning says that it is a repair service shop, excluding automobiles, any idea if leasing out storage space would be permitted?

That aside, If it were me I'd get a professional estimate of what repairs would cost, and make the decision to keep or sell based on that. 

If property values appreciate well, you might be sitting on a property that's worth a great deal more than todays ARV, especially if you can complete some of the repairs while your grandmother still lives there.

I thought I could solve the vagrant problem by buying and repairing the buildings.

Make sure when the new hardware is installed adjustments are made if needed and repair any damage to door jamb. 

The rental is currently managed by my husband and I and I do the paperwork and lease etc, and hire contractors or husband does light repairs.

The real property investment can be repositioned if it proves disappointing in its original form; it can be refinanced or recapitalized if it has too much or too e pensive debt; inflation over time bales out many bad purchases, and finally the investors knowledge, experience and abilities can be leveraged to turn around a cash flow negative property.I’ll provide an exampleThree years ago we purchased a note from a bank secured by two auto repair facilities with a large amount of excess land.  

Rental income and expenses, such as mortgage interest, property taxes, repairs, and depreciation, can be reported on Schedule E of your personal tax return, regardless of ownership structure. 

Budge for unexpected repairs.