Insurance policy for sub leased tour bus

[need to know]

I have a 1998 Prevost Bus Conversion. It is registered under my personal name and sits primarily in the garage at my business. Previous owners sub leased it for one month annually to a company that wraps it and hits the road to promote people, places and events in the entertainment industry. The lessor supplied the drivers and the insurance for the month that they were using it for promotion. I currently have the Bus covered under a personal RV type policy but it is used once annually for business. I want to make sure I have the right coverage. Should this vehicle be on a commercial auto policy all year and do I cancel coverage during the time that it is being sub leased? Can your refer an insurance provider that can help me?

Thank you,

Need to Know : )