Yes, you have to follow the owner specific house rules. The house rules are part of the rental agreement between the renter and the owner. If you don’t follow the house rules the owner has the possibility to hold back parts of your security deposit.
Remember, these vehicles are all privately owned and often heaps of private memories are attached to the vehicle. If the owner lets you be part of these memories it’s only fair to also respect his or her wishes and preferences.
To make sure you follow all the house rules it’s best to inform the owner about your plans (e.g. driving on dirt roads, bringing along you dog, etc.) and start a conversation.