Mileage often tells a more accurate story than the manufacturing year. Look for buses under 200,000 miles ; well-maintained diesel engines can last much longer, but parts wear out.
The classic "dog-nose" bus with a protruding engine. These are generally easier to service because the engine is accessible from the outside. buying a school bus for personal use
Avoid buses with significant frame rust. While surface rust can be sanded, "cancerous" flaking rust compromises structural integrity and is a deal-breaker. Mileage often tells a more accurate story than