This is part of the quest “Painting the Town”. If you reached this location before getting the quest, you can just loot the area, clear it of raiders, then mix yellow and blue paints using the paint mixer in the storage room to get the green paint which you can use later when you get the quest. The mixed paint has no weight so you can conveniently carry it around with you.
There's a Power Station at the back of the store, Weapons and Armor Workbench behind the store's counter inside. The Paint Mixer inside the storage room. (Part of the quest) Take the yellow and blue paint cans then mix them together using the mixer to get Green Paint. There's a sleeping bag in the middle of the storage room with an ammo box and duffle bag. There are also a lot of ammo boxes and toolboxes containing various ammo in the area
The second floor office has a Hardware Town Storage Key and an issue of Picket Fences on the table.
Beside it is a steamer trunk containing ammo and weapons. The room beside the office has a bobby pin stash, ammo on the floor, and a mattress. Unlock the next door with the storage key to find a Master Safe, bottlecap mine, stealthboy, and a duffel bag inside.