The price is the decision maker. I'd buy that thing in a skinny minute if it was around here...and if the price was reasonable. The engine and trans is worth a small fortune by themselves. A total should be in the $30 to $40K range? About 25% of blue book.
The wiring can be dealt with. If the buyer has a knowledge base for such work. You won't need 9/10s of the wiring for a bus conversion.
The engine/trans can easily be made to safely function.
How much, and where did you say this coach was located???
Insurance companies will definitely total things these days. And most of the time an individual will not have an opportunity to buy the totaled item. Buyers that pay roughly 25% of book are often contracted to buy the machine. They win some and they lose some.
The problem with increased totals has more to do with semi-crooked shops giving bad-faith estimates for repair. We get lowballed all the time, and it's obvious that repairs cannot be made for what is quoted. But we occasionally lose a job due to such chicanary. Crooked (smart actually) dealers will lowball the estimate, get the unit all apart, and then file a "supplemental" for "hidden damage" which will adjust the cost of repairs way upward...often above retail book. When that happens, the insurance company is trapped. The insurance companies usually pay. Not always. They are getting wise to that approach.
Where did you say the bus was located?