Two policies you already own. Neither one covers the toys.
Here is the assumption that costs people money. The RV is a vehicle, so the auto policy has it. The boat lives at the house, so the homeowners policy has it. Both feel reasonable. Both are mostly wrong.
Your auto policy does extend liability to a travel trailer, but only while it is hitched, and only for damage you cause to other people. It pays nothing for the trailer itself, nothing for what is inside it, and nothing at all once you unhitch, which is exactly where the trailer spends most of its existence. Your homeowners policy extends a little coverage to small, low-powered craft, generally under 26 feet and often only on your own property. A kayak, fine. Anything with a real motor, no, and the liability side is worse than the property side.
The good news is that this is a cheap problem. Recreational coverage is one of the least expensive things in insurance, and it usually bundles with your auto and home policies for a discount that softens the whole bill.
The bad news is that Arizona adds its own wrinkles. Wildfire makes a stored RV a total loss risk in a season when you are not even using it, which is exactly when owners are tempted to cancel the policy. Marinas here have their own insurance demands before they will hand you a slip. And Arizona doesn't require a boater education card, though taking the course usually earns a discount. None of it is complicated once someone walks you through it, and that is a fifteen-minute phone call.