If your RV doesn’t come with any USB chargers (I am so excited that mine does!) you will probably want to use a plug that allows you to plug USBs into it. Aukey has a super cheap charger, that is about the same size as the standard Apple iPhone charger, but instead of one USB port it as two. And the plug part is foldable.
I love the fact it is foldable, meaning I can store it easily in a tech essentials zip bag I carry without it catching and unravelling other cables I have stored in the same bag.
You will need to use the Amazon code AUK2PORT for the $7 deal.