As with frequent mechanical/electrical/gas services on a caravan, I have a regular "clean-out" for my caravan. Usually this is done prior to a long trip, but at least once a year. The whole van is unpacked, to the point of empty shell status. Amazingly, the stuff removed, inclusive of curtains and cushions/matresses etc, fills up one half of my double lock-up garage!! The curtains are washed and cushions etc. vacuumed. You'll be amazed at the amount of dirt collected over a period of 12 months!!
The shell is then also cleaned thoroughly, even inside all cupboards. Before this cleaning, it is worthwile to 'inspect' all corners & crevices for any mould build-up, signs of water leaks, unwanted ants or "gogga" activities. While removing last year's sand from the coast, you automatically recall the nice holiday! As ants/'goggas' nesting in a caravan present problems, I fumigate the caravan before packing everything back in its place. You'll be surprised at the unnecessary stuff that you cart along. Store it in a cupboard and should you require it for a specific trip, take it along, and remove when returning.
This whole operation is a family exercise (kids get into the corners of the cupboards easier than I do!) and a whole day is set apart for this. Thereafter you have a caravan that is cleaner and neater than a new one or one purchased from a dealer!!
Give it a try and see the pleasant results. It also wets the apetite to go camping again!! Regards