A duplex would work, too. Use one unit for rental and the other as the showroom. Find renters that would normally be gone during the times when you might need to demo the AV equipment. If the units have no internal common areas (like a single entrance & hallway that goes to both units), you don't need to worry much about someone breaking in without being visible unless they just want to cut their way through a wall.

AirBNB or VRBO are good ways to make money with a rental unit. I have a friend who owns the house next to his business and he renovated it last year- he gets a lot of money per day or week and it's nothing special. He uses VRBO and changes the code for the door lock just before check in time so nobody else can get in without a key. I'm pretty sure the building is paid for and even though he started renting it after the middle of last year, the rentals have more than paid for the renovation already.