On the insurance side of things I’d recommend the following:
Public liability insurance: as a tour guide, if anyone on your tour gets injured, they may try to hold you responsible. This is essential an essential coverage and you shouldn’t be operating without it.
Motor vehicle insurance: If you own the van, you’ll want to make sure it’s insured. You’ll need to request cover for damage and also third party liability - that is, if you hit another car and they hold you responsible.
If you need more information about this, best to talk to a local insurance broker. All the best!