This will be our 2nd year of caravanning, so thought we'd start by cleaning the outside of the van first but there are so many products to choose from, we don't know where to start! What do people find works best? Do all products have to be rinsed off? Ideally we'd like something easy to use that takes the minimum effort! Do you have to avoid your windows, or do any products clean your windows as well as the rest of the van?! Many thanks, Pam