insurance questions

1. Once I put the camper on the truck and head out on the road, do I need to inform my auto insurance company, i.e. does that change anything for liability/insurance purposes, i.e. would it cause issues if I got into a collision and hadn't told my insurance company about the camper beforehand?

2. How are you all insuring your actual truck campers? It's a high-dollar item (for me, at least), and I would imagine people want them insured.

Many thanks in advance.