When I drove a small school bus, and I needed to park it somewhere in between the times I was transporting students, I generally looked for a spot at the edges of the lot to back into, where the back of the bus would overhang over the curb (I made sure it would never disturb any sidewalk). Of course, I did several times see full-sized school buses diagonally parked across 4 spaces at the far end of a large parking lot; after all, there’s not much else you can do with such a large vehicle.
When I drove a small school bus, and I needed to park it somewhere in between the times I was transporting students, I generally looked for a spot at the edges of the lot to back into, where the back of the bus would overhang over the curb (I made sure it would never disturb any sidewalk). Of course, I did several times see full-sized school buses diagonally parked across 4 spaces at the far end of a large parking lot; after all, there’s not much else you can do with such a large vehicle.